Look very closely at her limping foot: are there any signs that something bit her or a torn toenail? check her pawpads for cuts or rocks that may be stuck in between the pads. if no, to all of these...seek a vet!
Once my cat was limping but that's because tape was stuck to his foot and I didn't notice. If you can't find anything attached to your kitten, ask another person's point of view. But sometimes cats try to hid their emotions they can't just say "I'm in pain". So then discuss it with a vet. She'll be fine =]