As an alternative to stronger drugs, you might want to buy yourself some time with minoxidil instead. Once you’ve reached around 20 you can add in 5AR Inhibitors, preferably dutasteride as others suggested. At that point I’d still keep minoxidil, just in case dutasteride sheds you harder at start - which it might.
Around 25, you can drop minoxidil, let your fake hairs shed off in like a month and by then you should have also saved up a bit of money for a decent transplant to fix your hairline. Have that done and stay on dutasteride to maintain until lighter drugs like CB-03-01 (Breezula) become available. Once something safer but effective comes - switch to it and maintain with that instead, for safety.
This would be ONE possible plan for you. This way, you should have your early youth covered (literally), then over a relatively quick year, you would potentially solidify a hair you desire via the transplant for the rest of your life. I’d personally rather you do something like this, as opposed to wasting years on these forums looking for a miracle. It just won’t happen. Feel free to make your own plan if you will though.
EDIT: obviously, you could just take a chance and try 5AR inhibitors early on to see if you respond well and to avoid a transplant later, plus it’s obviously more convenient than minoxidil. HOWEVER, to have that hairline at 16 is very alarming to me. A transplant might be essential at some point. Plus most derms and docs are typically quite clueless abt hairloss and will conservatively just prescribe u min anyway but there’s that route to exhaust as well, for some “professional” opinions if those help.
Still, your choice.