Don't be afraid to change instructors, if you don't gel with your instructor swap to one you do gel with. I did 13 hours at the age of 16 and was afraid to do exactly that. Long story short, I didn't make much progress, it put me off a little, so I went off to do other things for a few years. 6 years later I came back a little wiser and found an instructor and club I liked, and 9 months later I was a PPL holder. If I'd just had the maturity at 16 to admit that instructor wasn't right for me I might've had my licence much sooner!