It's very good (mejor: healthy, beneficial) to do exercise, especially during these times, due to covid COVID-19.

You see, people stay in their homes without movingand laze around, and that's bad for the body,. "wWhat you don't use will degenerate," they say.

However, it was so hard to do it well,master it, just like languages,. I thought I was doing it right, but when I saw how it was and allactually was supposed to be done and when I took note of mythe mistakes I wasthat I made, I felt so embarrassed.

So I did it over and over again, and now I think I becameam much better, but there's are still a lot of things that I need to improve yeton.

I started dancing in this summer.

It's very good to do exercise, especially in these times, due to covid 19.

especially, not specially (native speakers make this mistake too hahaha)

You see, people stay in their homes without moving and that's bad for the body,. "wWhat you don't use will degenerate," they say.

Just some small punctuation changes to make it seem less like a run-on sentence.

However, it was so hard to do it well, like languages,. I thought I was doing it right but when I saw how it was and saw all of my mistakes I was so embarrassed.

I think it would be better to find a way to split this sentence in two so it isn't a run-on.

So I did it over and over again and now I think I became better but there's are a lot of things that I need to improve yet.

things is plural, so 'are' instead of 'is'