Can you chang your DOB or Age on xbox live if you signed in with too young of an age?

I need to change my age or date of birth on xbox live. Does anybody know how to do that?Can you chang your DOB or Age on xbox live if you signed in with too young of an age?Sadly you can't. I know that it is really stupid, but you can either create a new account or just wait until you are 18. Also you could create a free silver account that is older than 18 to download rated M stuff.