I'm a 17 year old using the main account on AT&T. I switched over last year for the new iPhone from T-Mobile and my mom's name is on the account. She added me from the website onto the list of people that can make changes to the account. Does this make me eligible to walk into an AT&T/Apple Store on the 11th and purchase the iPhone 3G while extending the contract for 2 years even though I'm not the actual account holder?