First time.

I've been learning English for a long time but I haven't practiced it in real life and now I wanna do it.

This sentence is more natural (it flows better):

I've been learning English for a long time but I finally want to practice in real life. 

or 

I've been learning English for a while and now I want to practice in real life.

There are lots of ways to phrase this. (There are lots of ways to say anything in English) :)

Try not to use so many periods so that the sentence isn't so rough. It's also kind of awkward to start a sentence with 'but' or 'and'. I hope this helps a little. Keep up the great work!

First time.

I've been learning English for a long time. But I haven't practiced it in real life. And now I wanna do it.

I've been learning English for a long time, but I haven't practised it in real life, and now I want to do this.