Blah to all the dissenters, if the Doctor gave you finasteride at 16 whatever. I would relax a bit. Finasteride maintains hair in around 80% of guys for more than ten years, probably forever. I've been taking for more than 5 with no side effects.
There's an 80% chance that hairloss isn't something you'll have to worry about anymore, and if finasteride doesn't work for you there's not much you can do about it. The effectiveness of everything else compared to maybe dutasteride is abysmal, so why worry about it when you're doing as much as you can?
I wasn't sure if I was maintaining my hair until I was on it for three years so my advice is to take your finasteride and forget about it. You're not going to know for sure that it works for possibly years so don't waste your time thinking about it