Mine's a mixed bag, being a young'un myself (22). I find that it causes my beard to come in darker and faster which makes me look a little older between shaves
(I let my stubble grow a little between shaves as I find it makes my beard softer when I'm shaving and prepping).
However, when I'm clean shaven I have a smooth, pink and chubby face, which does make me look younger. It'll be interesting to see how things change once I get a bit older.