i had mine done when i was 3 i think, i dont wear any now, but always had them in.
my sister got hers done at 9 months i think she was, i remember her crying for a little bit loke 10 secconds, mum gave her a doughnut and she was fine, if they have sleepers in it wont annoy them at night.
i remember having my nose done at 11, my step dad was against it, but once it was done, he didnt say much after that, (my sister is now 12 and wants hers done, he went APE! so she hasnt got one yet)