You can push the tissue around in any vagina, it's got nothing to do with being a virgin or not. The vagina isn't solid, obviously you can press it and it will move.
Generally you can't tell if a girl is a virgin or not just by how she feels. The fact you couldn't fit in two fingers might mean she's a virgin but it could just also mean she wasn't very wet or she hasn't had sex for a while or is naturally small down there or you just weren't doing it right. If two fingers had fitted, that wouldn't prove anything either, because she could still be a virgin and masturbate with two fingers.
Just trust what she says, you can never find out for sure and it's not your business anyway whether she is or not, so don't drive yourself nuts wondering about it. If she lied and she regrets it then she will admit to it.
I have a vagina, fingers, and I used to be a virgin lol