My daughters are both well under 5ft and barely 90lbs, even into their 20's, and they both use a Rem 700 in 7-08. They've used it since they were way smaller than they are now with no problems. That would be my first choice, but as has already been said, your .270 shouldn't be much different with a 140gr or smaller bullet. I'd probably just go with that. No sense spending money you don't need to.