I'm actually not too sure about the age, I bought him/her from an expo, the breeder didnt really give me too much info

I feed adult mice, usually 1 a week, I just recently ran out of adult mice and have to get to a petstore for some more, I have alot of hoppers so last feeding (s)he got 2 of those within a week and a half. should I maybe start feeding 2 mice a week? maybe even go to small rats?