How strict are they on the age on Carnival Cruise line?!?

Me & my best friend are going on a cruise on the Carnival Elation ship, well I'm 17 and my best friend just turned 18. The Club 02 on the ship says for ages 15-17, but will they still let her in since she just turned 18 last month and be a little lenient or will they not let her in? & do they give you a card or something to swipe when you walk in and out to sign yourself in and out?