We saw it

Saw it yesterday with my DH and DS (he turned 5 in April.) My DS loved it! He's seen all the Ice Age movies. This one was cute. There were some somewhat scary "pirates" (a big monkey and an assortment of other animals) but my DS did not seem fazed by them, and of course the good guys prevailed. I definitely think it would be appropriate for your GS.

Hope that helps.

SJR