If ur snake is very small look at its belly. You may be able to so see a mark where it was healing from umbilical. When I got my normal she was tiny and I saw that so I knew she was only a few months at the oldest. If you can keep the entire tank at 80-85 while maintaining good humidity it should be ok. If ur snake has room to stretch out almost entirely then it should be ok. But you don't want the tank multiple times bigger than ur snake. F/t is preferred by most, including me cuz they can be kept in the freezer. It easier than breeding ur own or going to the store and hoping they have the right amount and right size. With f/t u don't have to supervise feedings. Just drop it in and move on to the next. And u can leave them in overnight when some will only eat it.