Well, it's hard to know if it's come in quicker if you've never paid attention to when you got peach fuzz, which I believe is always. It doesn't really come in thicker, but it'll feel and look that way because you're cutting off the soft end of it, hence it's a lot more pricklier and noticeable. You're not altering it aside from cutting it down to the thickest part.
I shave only sometimes, I haven't noticed if coming in quicker because I shaved it. Comes in at the same rate every time. I kind of do it in secret with one of my dad's shoddy disposables. I can't tell you if there's a difference, aside from how sharp it is.