Getting a Ball Python

My wife and I have been talking about getting a snake for about a week now, and today at her work someone just happened to come in and ask if anyone wanted a snake. It’s a ball python. I’ve been reading all day, but have a few questions.

1. I’ve read most places that say the temperature can be allowed to drop at night, but doesn’t explicitly say it’s necessary. I’m wondering if the tank must be cooler at night, or if it just can be? I don’t want to forget to turn the light off, or on and have ill effects.

2. The snake is about 1.5 feet long, and about the size of a 50 cent piece, can anyone estimate the age?

3. Can frozen mice/rats just be thawed overnight, or do they need to be soaked in warm water?

Thanks for the help.