Today, I found myself thinking about the fact thathow the year is coming to an end. Today, I found myself thinking about how the year is coming to an end.

Introductory phrase "today," needs a comma (,) "about the fact that" isn't wrong, but I just made it more concise with "how"

We will no longer be able to make "20/20 vision" jokes when asked where we see our selves in x amount of time, people who were born in the year 2000 officially will be 20 years old, and I must say, it feels kind of weird. We will no longer be able to make "20/20 vision" jokes when asked where we see ourselves in x amount of time, people who were born in the year 2000 officially will be 20 years old, and I must say, it feels kind of weird.

testing with the new changes to see if it will show "ourselves" properly

We will no longer be able to make "20/20 vision" jokes when asked where we see our selves in xX amount of time, and people who were born in the year 2000 officially will be 20 years old, and. I must say, it feels kind of weird. We will no longer be able to make "20/20 vision" jokes when asked where we see ourselves in X amount of time, and people who were born in the year 2000 officially will be 20 years old. I must say, it feels kind of weird.

"our-selves" from the previous correction is incorrect.

We will no longer be able to make "20/20 vision" jokes when asked where we see our selves in x amount of time, pnumber of years. People who were born in the year 2000 officially will be 20 years old, and I must say, it feels kind of weird. We will no longer be able to make "20/20 vision" jokes when asked where we see ourselves in x number of years. People who were born in the year 2000 will be 20 years old and I must say, it feels kind of weird.

FromAfter the 1st of January on, I'll have to get used to writing two 2s in the year when writing the date, for the next 10 years. After the 1st of January, I'll have to get used to writing two 2s in the year when writing the date for the next 10 years.

After the 1st of January sounds better. Couldn't find any examples of "From... on" to see if it was grammatically correct, it just sounded off to me. If you wanted to use that, I think you would need to say "From the 1st of January and on" but I could be incorrect. comma splice; no need for the comma before for. It made an unnatural pause.

From the 1st of January on, I'll have to get used to writing two 2s in the year when writing the date, for the next 10 years. From the 1st of January, I'll have to get used to writing two 2s in the year when writing the date for the next 10 years.

The end of the decade also makes me think about where I'll be in 10 years' time. The end of the decade also makes me think about where I'll be in 10 years' time.

Will I be doing what I love doing? Will I be doing what I love?

You can optionally drop the extra doing at the end