Stick to your guns Honeybadger and do it naturally.
If you are making gains of 5-10Ibs FFM there's no need at all to go the steroid route, no matter what age you are. I'm willing to bet my house that hardly any of the guys of your age using sauce know anything about PCT, never mind actually doing it.
Fifteen years old is one of the worsed ages you could even consider using steroids. Your own body is maxing out on its own T production. The only teenagers who should be using steroids are those who have stunted growth due to late puberty, or undescended testicles.
If you really do want to do it eventually, make sure you're at an age and level whereby the gains you make couldn't have been done naturally. For most guys this is usually in their mid to late twenties, at the earliest. For now, bust your ass in the gym, eat clean calories and lots of them, and study all you can about the hormonal compounds and steroids out there. And learn about post-cycle therapy too; very important.
For now, if you feel you do need to boost your progress at any point, then look at the natural nutrition and herbal supplements out there. Check out the stores and Needtobuildmuscle shop here at EF. You'll find loads of ideas and products for boosting hormone levels of testosterone without going the steroid route. What's more...they're all highly effective.
Best of luck dude!
Craig