I am, no sides besides the ones I imagined for the first few weeks & I’m pretty much already done growing.
You’re not done growing, you’re 16 . Even if you’re at your max height and skeletal development (unlikely at 16) you still have brain and sexual development which is heavily reliant on androgens which you’re restricting by taking finasteride. Not a good idea at all.
Consult a Doctor and get an opinion. How bad is your hair ? Have you posted any pictures ?