I am 30 years old and I have never been keen on sports until four years ago I took up with MMA, I don't know if was a good idea starting with this rude aggressive/violent sport but I did it. I went to a small academic trainer/coach to learn different techniques like how to throw punches and kicks and in few time I soon got used to the training. I kept fit and I felt I was healthier. It's a good thing to do because you can make friends with similar interests. It's also a great way to learn much more. Because of my job I couldn't continue to training in mma and I lost all my effort put progress in it , but sometimes I work out in my home or have a brisk go on a short walk trying to avoid a sedentary life, I hope in a the near future I can return back to the academic trainer/coachand start training again.

Think you should wait for an actual English teacher to answer this before you take my advice to heart but... In most situations, "could" implies multiple options. For example, when I say "You can eat," that usually means you're able to eat now. If I say "You could eat" it is usually followed by an "or". For example, "You could eat, or you could stay in your room." Again, you should wait for an English teacher to answer, but as a native English speaker that is generally how I use it. Hope this helps

You were in my house that night. They did exercices for two hours in the gym. Leonel and his friend went to the coast of Havana. She paid the water bill. The people believed that the illusionist did real magic. Karla put her Spanish books on the table. You knew the whole truth that day. I had to run very fast to not get wet.

Editor's Note: Your past tense is perfect. I just made one change to make the sentence less awkward. I wrote the change in bold letters.

Keep up the good work! You're doing well!!