I like to sit as close to the stage as possible, and when I saw Matilda I sat in the 4th row on the center aisle. I remember thinking I could have picked seats closer, even the first row. I think you should take those seats, especially if they are regular priced seats and not premium priced. It will solve the problems you mentioned.
If you do get them, check with the house to see if they have any booster seats for kids just in case your child has trouble seeing. Not to give anything away, but there is one scene in the musical where the characters get really really close (not in a scary way) to the first couple rows, so your child will enjoy that if you are sitting in the front.
Matilda is a wonderful show, my favorite by far of all of the kid friendly musicals which are currently open.
Updated On: 8/17/15 at 01:56 PM