Yeah, it probably comes from being taken away too early. Mom and siblings would be the ones to teach her how to use her claws, and since they speak kitty language it would be a much faster process than you trying to teach her! It could also have to do with the fact that she's still a very young, wobbly kitten who's using her claws to help herself stay balanced.
I don't remember what kittens were like with their claws, but make sure you keep them trimmed, and make sure you don't encourage any rough play with your hands. If you're petting her and she starts clawing at you, stop petting her. When she stops, pet her again, if she does it again, stop petting her. Repeat until she learns that clawing you while you're petting her means no more loving. Also, avoid belly rubs, I don't know if you are, but we all know how irresistible cat tummy's are, especially little kitten bellies, but a cats belly is a really vulnerable area, and it results in claws being unsheathed when you pet them!