I had one of those black chin hairs since I was about 15. Got to about 3 by 18 and that was it pre-T.
My hair (or fuzz) has always grown longer on the chin and sides, and corners of my top lip, where it was brown.
If you shave the fuzz, then yeah - the blunt hair ends will feel rougher and more like stubble.
I'm about 6 weeks on T, and the hair growth is coming in in a similar pattern to what was there already - it's just denser, darker, and the growth area has spread. I need to shave every 2nd day instead of every week.
I noticed what could be mistaken for an increase in body hair pre-T, but I think it's a combination of appreciating what you have, and actively looking for more hair. Though some people do get hairier as they get older (up until mid 20's, maybe 30?).
Letting PCOS run rampant and cutting any birth control will help. I lost a lot of body hair when I took that stuff (I've never had PCOS though, just insanely high T levels for no apparent reason). I didn't need to shave my face at all.
I'm going to grow myself a nice mo and short goatee combo when the hair comes in. Joined, of course. And maybe some longer sideburns to go with that

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