At first...

Well, Hi, my name is Sveta and I'm from Russia. This is my first experience with such these kinds of sites. Because of that this note will be short :)
I really want to make my English better. Also I can also help you with Russian, if it needed.

The word "well" sounds fine when you get up to speak in front of a crowd of people but I wouldn't start writing with it. The first two sentences were so short, it's better to connect them. The next one can be said in different ways, like "this is my first time on this type of site". I'd probably say "that's why" instead of "because of that". And "if needed" at the end is probably better said "if you'd like" or "if you're interested".

At first...

Well, my name is Sveta, I'm from Russia. This is my first experience with such kind of sites. Because of that this note will be short :)
I really want to make my English better. Also, I can would be glad to help you with Russian if it is needed.

Welcome to the big family Цвета^^