Can any one tell me how to change the age set on Xbox 360 Live?

I need help because i accidentaly put the wrong age (year) i was born in 89 but i put it as 92 (apperently.. i have no idea how i mixed that up). Know it wont allow me to download any M rated demos off Xbox Live. It is really getting me angry because all i can pick from are like Viva Piniata and crap like that(no offence to Viva Piniata lovers) . Before Xbox Live updated in January or so i was able to download them so i didnt really care but know it really gets me mad wen all these new games came out. Please if anyone knows how please tell me...Can any one tell me how to change the age set on Xbox 360 Live?The best way to take care of this is to log on to xbox.com and go to my account in the top right hand corner. You can easily adjust your age there. Viola, no more problem.