Hi Jonk,
You are too young for a HT, no Dr recommended on this forum will accept to do a HT on a 19 y/o patient, unless it's a very particular and rare case, I am sure of it. Try Revita shampoo, I use it and love it, if you start young you might get nice benefits, it will stimulate your hair and scalp, it's not a miracle cure but a nice mild treatment. I am not sure taking Finasteride so young is a good idea, I would consult with a Dr to make sure. You came to the right place for advice, over here you'll get all the answers you need.