We took ds when he was 15 months old. He wasn't quiet walking on his own at the time. He easily walked around holding furniture or hands, but not on his own (about a week after we returned home he started walking).
First, I have to say BB is A LOT bigger than I thought. We only allotted one afternoon and you can easily do a whole day or two there. ds and I basically played in the kiddie area, which is very nice. When we went to the tweeny area for dd, ds and I just walked around a bit and played in the water.
If you are DYING to see BB, I would go with an infant. 10 months is old enough for sunscreen. Bring baby hat and shade stroller and you'll be fine! Sandra