Birthday cake question

Shoshi10

DD's party is this weekend and I ordered a quarter sheet cake. The grocery store says it feeds 20 people. We just added on a few extra people that are coming now, so I have about 25 people who will eat cake. I was talking to my friend about it this morning and she says that is not enough cake and I should change it to a half sheet cake (feeds 40 people), because it's better to have way extra than to serve smaller pieces. For dessert we also are serving cookies, brownies and a fruit platter. With those extra desserts, do you think the quarter sheet cake is fine? We are having it at a park and I don't want to have a bunch of leftovers to bring home with me.