What should my corn snake be eating

Hi all. I think I have a 2 and a half years old female corn snake, the reason I am unsure of her age is because I adopted it in February this year when the previous owner told me she was a he and also 3 years old. I took her to my local pet shop which specialises in reptiles and are really good say it's not a he but a she and she seems more on the 2 year old side as she was small.

When I got her she was on rat pups, now she is on small weaners I'm pretty sure (have to look on pack), I was just wondering if there is a feeding guideline I can go by and also to see if she is a healthy weight or underweight because I also have a 11 month old boy to so it would be nice to see if I'm in the right area

Thanks all

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