I sawwatched a movie in thea lecture room for the people who want to get the renewedas part of the drivers' license renewal process.

saw -> watched
"Saw" is more like 見る whereas "watched" is more like 観る.

in the lecture room for the people who want to get the renewed drivers' license -> as part of the drivers' license renewal process
Instead of saying the lecture room is for people who want to get their drivers' license renewed, say it more like you did in Japanese. Say that the movie itself is related to the drivers' license renewal process.

There, I knew a new technologylearned of self- driving car systems.

knew -> learned of
"Knew" means that you were already aware of something existing. Since you're talking about discovering self-driving cars, "learned of" fits better since it's the same meaning as "discover".

a new technology of self- driving car system -> self-driving cars
"A new technology" isn't incorrect English but in this case, it sounds a bit unnatural. Keeping it simple is best.

It means that a car whichThese cars are cars that can drive without drivers.

A persSomeone haves to sit on the car seat but they doesn't need to grab athe steering wheel anymore.

Actually, I was born and grew up in Tokyo's city area Tokyo.

The phrase "was born and grew up" is apparently used commonly. But, I feel that it may be more natural to keep the verbs either both active or passive. The verb phrase "was born" is passive and the verb phrase "grew up" is active which makes it less consistent.

Other options:
Actually, I was born and raised in Tokyo's city area.
Actually, I grew up in Tokyo's city area.

Thus I have been thinkingalways thought that I don't need to drive a car.

have been thinking -> have always thought
"have been thinking" means that you've been thinking about it in the recent past and now. In comparison, "have always thought" means that you've been thinking about it for a long time (in the distant past continuing until now).

Since I can choose various kinds of transportation, including JR, subway, bus, … etc.

kind -> kinds
Since you're talking about multiple things, it should be plural.

However, I moved to a rural area.

As a result, I have to drive a car even though for just a small thing to doeven for small errands.

drive a car -> drive
Not a correction, more of a suggestion. Just like in Japanese, you don't have to mention the car. This is because most people would assume you're talking about a car when you use "drive". Of course, it's grammatically correct too even in formal writing.

even though for just a small thing to do -> even for small errands
"Even though" usually comes before independent clauses. Independent clauses are basically a combination of words that can be their own sentence.
Some examples:
"Even though she didn't want to do it" = "Even though" + "she didn't want to do it"
"Even though allergies can be deadly" = "Even though" + "allergies can be deadly"

Based on the Japanese text, "errands" fits best because you're talking about things you need to get done, and that's what "errands" means. If there's a word for a concept, English usually prefers the word. That said, you could also write that part as:
"As a result, I have to drive to get even the smallest things done."
But since the Japanese keeps it simple with 用事, I think using "errands" is still best.

I wonder how many more years I have left to keep my body activelmy body can stay healthy enough to drive.

Another option:
I wonder how many more years I can stay healthy enough to drive.

The difference is whether you want to focus on your ability to stay healthy or your body's ability to stay healthy. In other words, do you want to say it like you're worried about your strength of will or the durability of your body?

Or will I someday do I have to return my license to the traffic police?

No, I don't want to.

Buin the near future if thet, if self - -driving car systems soon become popularcommon, it would be a good news for aging people.

Don't we need to get driving skill seriously?

Not sure what you meant by this.

It's a destiny forward people to get old.

Using "a" before "destiny" usually only happens when you're talking about multiple possibilities. As in, "That's a destiny I don't want fulfilled". To talk about "destiny" as a concept or in general, use "destiny" only.

But now, I'm believ have faith ing new technology and a brighter future.

I saw a movie in the lecture room for the people who want to get the renewedir drivers's license renewed.

There I klearnewd about the new technology of self- driving car systems.

I assume here that you learned about self driving cars at the place where you got your driver's license renewed.

It means that a car which can drive withoutThese are cars that can drive themselves without a human driver.

A person would have to sit oin the cardriver's seat, but doesn't need to grab ause the steering wheel anymore.

A 'car seat' is a seat for babies to sit on in the car to keep them safe. We would say "the steering wheel" instead of "a steering wheel" because there is only one steering wheel in any car.

Actually, I was born and grew up in city area Tokyo.the Tokyo metropolitan area.

Thus I have been thinking I don't need to drive a car.,

Ssince I can choose various kinds of transportation, including JR, subway, bus, … etc.

I'm connecting the two sentences here. Any sentence that starts with 'since' is an incomplete sentence (a 'dependent clause' in grammar terms) and must be connected to a complete sentence (an independent clause).

However, I moved to a rural area.

It would sound more natural if you specified when you moved. So, for example, "However, two weeks ago, I moved to a rural area."

As a result I have to drive a car even though for just a small thing to do.for small errands.

I wonder how many more years I have left to keep my body actively enough to drive.

Or someday dowill I have to return my license to the traffic police?

"someday" is in the future, so you would say "will I have to" rather than "do I have to"

No, I wouldon't want to. do that.

Turning in your driver's license is something that will take place in the future, so you can't really say you don't want to do that, but rather that you wouldn't want to do that. Also correct is "I won't want to do that"

But in the near future, if the self - driving car systems become popular, ithat would be a good news for aging people.

Don't we need to get driving skill seriouslycessarily need to learn how to drive?

It's a destiny forward people to get old.Everyone will get old eventually.

But now, I'm believe ing new technology and a brighter future.

If you're describing a general fact about yourself, for example that you generally believe in such and such, then you would use simple present. Usually the verb "believe" is conjugated in the present simple, though there might be exceptions. So for example if your friend was convincing you that he saw a ghost, and he was convincing you, you might say, "I'm believing you more and more"

I saw a movie in the lecture room for the people who want to get the renewedir drivers' license renewed.

There I knew afound out about the new technology of self- driving car systems.

It means that a car which can drive without a driver.

A person haves to sit oin the car seat but doesn't need to grab athe steering wheel anymore.

Actually, I was born and grew up in the city area of Tokyo.

SincThis is because I can choose from various kinds of transportation, including JR, subway, bus, … etc.

However, I moved to a rural area.

As a result I have to drive a car even though for just a small thing to doerrands.

I wonder how many more years I have left to keep my body actively enough to drive.

Or someday dowill I have to return my license to the traffic police?

But in the near future, if the self - -driving car system becomes popular, it would be a good news for aging people.

Don't we really need to gethave driving skill seriouslys?

It's a destiny forward people to get old.

But now, I'm believing in new technology and a brighter future.