if i have a daughter i'd get them done as young as possible, otherwise not at all.
my mum got mine done when i was 3 and they got terribly infected because I'd play with them and not let her clean them. it took me another three shots to get them done, and to get them to stay and by that stage i was 21.
i know it's a touchy subject for some, but I don't get the big deal. they're holes. if you take them out they close up.