That is the most sought after PS in all of Disney, and reservations are gone within minutes at 90 days out. You still might have a chance of snagging one, but you'll have to get on the phone every day and call and see - even once you're there you can try and see. There is a deposit on PS there, so some people will cancel before 48 hours prior to avoid losing their deposit, so you can hit it hard those days... just start calling.
There are other princess meals to have, if you can't get into that one, if you have your heart set on it. We have snagged PSB but never tried for CRT. I think the food is okay, you're paying for atmosphere and character interaction. There are bajillions of threads on here about people's experiences if you want to do a quick search =)