How about:
I'm Sixteen and you're not!! Ha Ha Ha!!! Now go back to your stressful job, piling bills, and oppressive mortgages while I enjoy being Sixteen!!!
That's what I would name her if I were sixteen again....
PS You'll need a large transom and small letters
Judging by the date on the OP, I'm thinking you're a little late on that one. Hope it didn't have any issues...HOLD ON THERE!!