IN DIRE HELP HELP HELP HELP?

Okay, so when i first got my xbox i decided to put my actual age not thinking it would change anything but it obviously did. so my cousins boyfriend set it up for me and put him as my "parent" and what not on there. but now they broke up soo.. i want to completely reset it so hes not on there and to where i can change my age and stuff. how do i do this!?