FlyerTalk Evangelist
Join Date: May 2012
Location: MCO
Programs: AA, B6, DL, EK, EY, QR, SQ, UA, Amex Plat, Marriott Tit, HHonors Gold
Posts: 12,809
I was very rarely carded before turning 21, domestic or international. Even in SkyClubs my experience was that I was carded far less than I was just served.
It's of course possible that you will be in which case you'll probably be denied. I'm not sure how old you look, chances are if you look pretty adult and not a drunken mess, you'll probably just be served without question in my experience.