I loved working with children and staying fit through swimming.
What I wish was different
I wish that the weather would have been nicer on cold days. It's no fun teaching in the rain while you and the kids are shivering.
Advice
If you plan on buying a wet suit, learn from my mistakes. Wet neoprene (the main material of wet suits) smells like skunk which in turn smells like marijuana. Try Patagonia's Yulrex wet suits. No weed smell there.