You don't have to retake your prereqs. Mine were 6+ years old and it didn't affect anything (there are a few schools with limits, but they are a small minority). You may want to consider taking a few upper division classes to demonstrate you still have what it takes. That will also allow you to meet a few professors and get some current LORs.
I don't think there's any schools that prefer older students, but I didn't feel discriminated against either (and I've got a few years on you). Good luck.