If you get someone 21 or over to take you then there won't be any issues.
That hilarious...went to buy some 22 LR the other day and the register prompted the cashier to ask if it was for a rifle or handgun, she was didnt believe me when I told her that if I said rifle it would ask if I was 18, pistol it would ask if I was 21.... so she rang up a box as pistol, asked if I was 21....