In a lastprevious post I wrote that I talked with a British "boy" but it was a mistake.

You can say "a previous post" to refer to Day 27, 26, 25, etc. If you say "the last post", that can only refer to Day 27, the post immediately before this one. "A last post" isn't correct.

He is actually seventeen so he's not a boy,. I didn't know that "boy" is a synonym of child.

"Boy" can sometimes refer to a male child under 18 years old. It depends on the context, I think. Some people might call a 17-year-old boy a "young man".

I think that I should try speaking more with him as I like so much the bBritish accent, that's the reason of a lot. That's why I started learning English in the first place.

I chose "That's why I started", but you could also say "That's the reason why I started" or "That's the reason I started".

The last year inLast summer I tried running, which I consider a sport, and I liked it so much.

MFeeling my heart pumping fast andwhile listening to my favorite playlist was sucho excitementing.

EI even I cut sugar and junk food andout of my diet. I used to run almost every day to tryin order to improvinge my velocityspeed.

Put "even" in front of the word you're emphasizing. "Even I cut sugar" makes it sound like you cut sugar out while someone else didn't. In your case, you should put it in front of the verb to emphasize that you cut something out instead of keeping it in your diet.

Sadly, I got and injury ined my left leg and I, got depressed, and I returned to eating junk food and all that stuff.

I'm going to try running again but I'm not really excited about it at all.

"I'm not really excited" sounds like you might have a little excitement, but not a lot. "I'm not excited at all" sounds like you have zero excitement. I wouldn't combine them.

I really like some sports.

In a lastprevious post, I wrote that I talked with a British "boy", but ithat was a mistake.

He is actually seventeen so he's not a boy, but I didn't know that "boy" is a synonym of child.

In my opinion, it's okay to refer to someone as a "boy" whether they're a teenager or a younger kid. It might be different if he was in his twenties or over. Then you might want to refer to him as a "man" or even just call him a "male".

I think that I should try speaking more with him as I like so muchto him more as I really like the bBritish accent, t. That's the reason of why I started learning English in the first place.

The last year inLast summer, I tried running, which I consider a sport and I liked it so much.

My heart was pumping fast and my favorite playlist was suchplaying excitementdly.

EI even I cut sugar and junk food, and I used to run almost every day to try to improvinge my velocity.

Sadly, I got and injury in my left leg, and I got depressed and I returnedwent back to eating junk food and that stuff like that.

I'm going to try running again but I'm not really excited at all.

I really like somedifferent sports.

I think that I should try to speaking more with him more as I like sto muchhear the bBritish accent, that's the reason of why I started learning English in the first place.

Good sentence, only a few little changes will make it flow better.

In amy last post I wrote that I talked with a British "boy" but it was a mistake.

He is actually seventeen so he's not a boy,. I didn't knowrealise that "boy" is a synonym of child.

I think that I should try speaking more with him as I like so much the british accent,his British accent so much, in fact that's the reason of why I started learning English in the first place.

The lLast year in summer I tried running, which I consider a sport, and I liked it so much.

My heart pumping fast ands I listened to my favorite playlist wasbrought me such excitement.

EI even I cut sugar and junk food and I used to run almost every day to try improving my velocityspeed.

"velocity" sounds a bit technical, and is better used with objects.

Sadly I got and injury in my left leg and I got depressed and I returned to eating junk food and all that stuff.

In amy last post I wrote that I talked with a British "boy" but it was a mistake.

He is actually seventeen so he's not a boy,. I didn't know that "boy" is a synonym of child.

Some people use "boy" or "girl" for people who are under 18 years of age, too, so it's not necessarily a synonym for "child."

I think that I should try speaking more with him as I like so much the bBritish accent, t so much. That's the reason of why I started learning English in the first place.

The last year in sLast Summer I tried running, which I consider a sport, and I liked it so much.

My heart pumpinged fast and listening to my favorite playlist wasprovided such excitement.

EI even I cut sugar and junk food andout of my diet. I used to run almost every day to tryin order to improvinge my velocityspeed.

oh, that's too much. I would run no more than 4x a week. There's also a 10% rule to protect our physical condition. It means that we're not supposed to increase our mileage more than 10% per week in order to avoid injury. If you search for Couch Potato 5K, someone has listed a freely available schedule for it. It's a starters guide to begin running safely.

Sadly, I got and injury ined my left leg and I, got depressed and I returned to eating junk food and all that stuff.

oh, no!

I'm going to try running again but I'm not really excited about it at all.

I really like some sports.

In athe last post I wrote that I talked with a British "boy", but it was a mistake.

I think that I should try speaking more with him as I like so much the british accent very much, that's the reason of why I started learning English in the first place.

The lLast year in the summer I tried running, which I consider a sport and I liked so muchit a lot.

My heart pumping fast and my favorite playlist was sucho excitementing.