If I have a party of 22 on Friday, December 14th, at 2:00... should I make reservations, or do you feel you accommodate that many at that?

Yes you should call and make reservations

I would make a reservation honestly. It can get quite crowded and you'll most likely want space for your group.

If you want to use the play place or have a central meeting place you might need a reservation. If you are just going to the aquarium to walk around and visit, you might not. I'd still call and see what they say.