Tickets for the show start at $48 and you can order them online. You can also enter the ticket lottery for select seats at $25 (see details on this process here). Whether you enter the ticket lottery or not, you'll want to plan to arrive 30-40 minutes before showtime as there is some additional security screening going on right now, and bags are not allowed inside the theater. The show runs about 2 hours and 10 minutes and there is one intermission where drinks and snacks are available for purchase. If your child can sit that long, I would say they will love the show!
This is a two-week only limited engagement, so clear a night on your calendar and take your children out to enjoy a magical night with Cinderella at the National Theatre. I think you'll love everything about it!
Disclosure: I was provided with 2 tickets to review Cinderella at the National Theatre. All opinions are my own.