Disney and universal Florida. How to do both..

I think You should do it. That 16 years old, is getting to the point where they often don't want to go with the parents so much.

Yes it will be hot and crowed, kids will still have a great time. Don't let some old grumps like me scare you off. ( we have been 4 times in the last 25 years, we are just kind of done with it) Kids always loved it though

If you are there three days, maybe just do 2 days at the parks, and spend one day hanging around swimming etc. Just a thought