Hi: Oh no.. babies are fine, as a matter of fact - there were many toddlers in the breakfast area, there were teenagers who could not look up from their phones as well as in the pool. There were also kids who were on their way to baseball games. I also remember seeing some teenagers who were like with a basketball group.
So I think any age will be fine.
Get an answer from Fairfield Inn & Suites Orlando Lake Buena Vista staff and past guests.