It's really common for someone to bleed after sex, fingering, whatever because the vaginal wall can easily be scratched (especially by fingernails) and in the heat of the moment you might not realize it. It could've been that, it could've been her period. As long as it's not really profuse bleeding, there's nothing to worry about.
What are you using as birth control when you do have sex? Because even if you do not orgasm in her, she can still get pregnant. I just wanted to make sure you knew that.
If you go to a doc, she can leave her mom outside (which she will want to do anyway because it's really awkward if you don't) and tell the doctor privately. It is important to tell the doc the truth, and the doc will not tell her parents. He will also likely prescribe her with birth control at this point, if she wants it, because she is having sex. If she doesn't want her mom to know that, she can convince her that it is to regulate her periods (which is a perfectly legitimate reason, especially for her right now) or something else, like to lessen cramps, reduce acne, whatever. All good reasons.
Every woman should start going to the gyno once she is sexually active.
No, a doc can't tell if you're a virgin unless you have stds or are pregnant or something. But in this case, it will be important to tell the doc about her sexual history, because it may matter.
Anytime sex is painful, you should get it checked out.
