Info on rosy boas please! ?

I am hoping to add a rosy boa to my home this week. It will be my very first snake. I talked to her current owner at length tonight. She says she is extremely tame and wonderful snake. She said she is about 2 1/2 feet long, about 3 1/2 years old, and only eats one pinkie mouse (frozen then thawed) a month. The girl seems to know about reptiles etc but everything I see on rosy boas says she should be eating bigger food more often. Is it a snake to snake thing? Anything else I should know about rosy boas?