My son was not quite 3 when I booked my upcoming January trip back in October. He turned 3 November 8th and the Disney people ABSOLUTELY REFUSED to sell me a ticket for him until he actually turned 3. It was the most ridiculous thing ever!!! I finally requested one CM ask her manager and she came back and told me if I kept my mouth shut I could save some money. (I did end up buying him a ticket.) Anyway, your ticket price definitely goes by the child's age at the beginning of the trip. Judging from how much trouble I went through to get my THREE-yr-old a ticket, you should have NO problems!!! In my case I would have felt like a cheat, but in your case it is TOTALLY legitimate to not buy a ticket.