Hey there dude, cool to see your story here and in some ways reassuring, too! Allow me to ramble a bit...
This feels kind of absurd to read, because our situations are in many ways completely the same.. I'm only 23, but started hair loss around 4 years ago as well - similar to you - but didn't do anything about it at first because the hair loss was so aggressive and I went from a perfect NW0 to a NW2.5ish in a matter of 6 months, so I figured I'd have no chance keeping that not to mention regrowing any hair. Well, it didn't actually progress much: at the moment I am something like NW3, which is not a bad drop in 3 years or so considering the first 6 months made me go from 0 to 2.5, and I've been on the treatments for about 5 weeks now, similar to you.
Similarly, I also am the most concerned about my thickness on the top. My hairline itself is a solid NW2-something (and has baby hair at the temples to make it seem like it's kind of normal and not a high and mature hairline), it's just that the thickness on the top effing sucks which makes my hair loss look like closer to something like NW3 Vertex -type of hair loss, if I grow my hair to be longer than a few millimetres long. There are no full on bald spots there, but the hair is ridiculously thin so my scalp is totally visible from certain angles if I don't style my hair well. I could pull off some hairstyles that made me look like a normal NW2 (assuming you didn't stare at me from above in a well lit room) before I got on finasteride, but after starting finasteride, I have had a MAJOR drop in the thickness of my hair, so I can not actually pull off the same style anymore for now. So even in that regard, I am in the same boat as you.
Also, even though my top thickness has been destroyed in these 5 weeks or so of finasteride, I feel like some of the hairs at the edges of my hairline, like the baby hair spots around the temples etc. are getting a bit fuller and I can see some growth there in surprising areas.. It's nothing to write home about, but I also have an optimistic feel about this, as it seems the stuff is working, even if my hair looks like s**t temporarily. So in that way, I, too, am hoping for more shedding, so the hair can come back stronger than ever, with thickness and some regrowth if I get lucky...!
Sorry for the rambling man, but I could just sympathise with you somehow, so I felt like bombing your thread a bit with a longer post! Keep updating this monthly or something - I'm keen to follow your progress! Here's hoping for regrowth and thickness for us both!
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)