As above, the food is apple juice and a cookie. You aren't there for the food; you are there for the performance. It is cute.
If a 13 year old is taking it at all seriously, she is probably too old. On the other hand, I had a group of 17s and 18s who wanted to do it as a bit of tongue in cheek fun (one girl had played Alice in a school play...) They thought it was a blast.
Tickets--guest services on day 1. They are free but very limited. The concierge will also have a stock. IF you get tickets and decide to do something else at that time, PLEASE turn them in at GS, even at the last minute. There are often families wanting to attend who were unable to get tickets; they will be thankful for your change of heart.
If you don't have tickets, you might want to go to the area anyhow. On one recent cruise, they had 2 lines--one for guests with tickets (got in as soon as doors opened) and one for guests without tickets (got in IF there was space). They've finally realized that wasting the space of guests not showing up doesn't serve anyone.