At your age that's not really a "bad habit"; it's more indicative of an unexperienced hiker. I'm not blasting you, we've all done that; I had a very tough time with that way of cycling when I first got into it. And it's why, or at least a factor, in why so many young cyclists lose to older, yet more experienced cyclists -- and this can be seen in many other types of activities, including hiking.
Average speed is a funny thing.