[Penguin23]

I don't know how young she is, and what her background is but if you really care for her then pay for a visit to a gynae to make sure that she is not suffering from vaginismus. This is a very painful condition that makes sex positively unbearable, but it is treatable

If you force your way in, and she gets the idea that sex is super painful then she will not enjoy it at all, and don't expect to have sex with her much in the future.