I'm not a native speaker, so I don't know the difference between pretty and handsome (I always thought "handsome" is the male equivalent of the female "pretty")  - so I'd call him handsome.

I would think he is in his late teens or very early twenties (maybe because of his eyes which I think are just a tad to big for an adult).

He has a certain boy-next-door charm. Although his smile indicates that he isn't a boy anymore ...