I have that baby-face syndrome without the beard and I thought it would be the same with one, so I grew it out during October and November. It doesn't get that thick or long when grown out, perhaps almost an inch, and the hairs like to pick certain spots as to where they grow and the itching is worthy of being a torture technique the government can employ on terrorists.
However, while it was grown out, I definitely noticed a difference in how people interacted with me, whether I knew them or didn't. People I knew thought I looked more mature with my so-called beard, and I didn't get carded one whole time when I went to a bar lol. I shaved it recently but I think I may have to include it in my look now. I wouldn't mind looking 27 instead of 19 these days.