One thing I would recommend is to try and stay focused. It may be different for you if your not paying, but when I started to run out of money after 40+hrs I had to stop flying for about 6 months to save up again and really lost interest. I got back into it eventually but I never really enjoyed it, as everytime I booked a flight, the weather forced me to call it off. The less you fly, the less you want to fly (at least for me...maybe I get bored easily).
Knowledge is power, the more you know about flying the more enjoyable it is and the easier it is in the air too.
You must be coming upto exams at school now at your age whatever country your in, so don't get too wrapped up in flying, the rest of your education is just as important. Your very young, you've got plenty of time ahead of you, enjoy your life, don't rush anything.