How to change my profile? It has my age incorrect

lol - I know this is kind of trivial, but I noticed when I go to my home page that it says I am 31 years old and I am 30. I guess I somehow incorrectly put in the wrong date. I've went to my profile to change it but it doesn't give me any options to change my birthdate so perhaps I'm looking in the wrong section. It is trivial, like I said, but hell I don't want to age faster than I already am lol. :-p