If she's pretty good at sitting still, she might be okay. Bring something quiet to distract her- maybe a coloring book? I had a seven and eight year old the first time I went and based on their personalities, I knew I wouldn't have a problem. I did come armed with Disney stickers, so when the two year old next to us started fussing, I whipped them out and gave them to my daughter, and with a nod from the other mom, had her entertain the child with them so I could enjoy the show. You know your child best, but my guess would be armed with something quiet to do, a well behaved 4 year old would do fine - especially if you did the earliest show, or took a break before the later shows.