You've discovered the world of lucid dreaming! It's one of the most enjoyable things you can possibly have happen when you're asleep. As a teenager, I used to be able to do it all the time. As I've gotten older, the times I am able to enter the lucid state while remaining in a dream have become fewer and further between, but every so often I'll have a happy accident and boom, there it is. Enjoy them while they last! :)