Is it bad to separate cats?

I plan to go off to college in the spring. My cat Skittles is 8 and Precious is 5. Skittles mainly only takes to me so I know I have to take her with. Precious take well to my mom but not too much to me. Skittles and Precious get along but then again they have their moments where they like to play fight. I'm not sure if it'd be better to take or leave Precious with me. My mom doesn't want me to and frankly I don't either but I'm not sure how Skittles will take being alone. My mom says to just leave Skittles but shes real nervous around other people and sleeps next to me every night. What should I do?