From what I’ve read, male pattern baldness is progressive, as in once it starts it continues. At that point it’s your genes that dictates how fast or slow you will lose hair. Your genes also dictate your level of hair loss and what Norwood you will stabilize at. I’ve been on hair loss forums for many years and read a few stories where people talk about their relatives that lost hair relatively early and became a Norwood 2 or 3 and kept that for many years.
personally, I think the best way to see what your Norwood destiny is would be to take a look at your relatives (father brothers uncles grandfathers etc) and see what kind of patterns there are and which you resemble the most to give you a rough idea of where you’re headed.
with that said, treatments can slow/delay and in a lucky population stop progression of hair loss so look into that as well.