How long does it take for a woman's vagina to get accustomed to have sexual intercourse (meaning no pain and no blood)? Is it normal to continue seeing blood during intercourse after the first time for the few weeks that follow?
No it is not normal. She should have an examination. The usual cause of this is a friable (bleeds easily) cervix. It is not dangerous, but needs to be evaluated. I am a gynecologist.
If the cervix is infected, it may bleed even with gentle intercourse. An examination would find any worrisome areas on not only the cervix but anywhere else in the vagina or labia. This could be as simple as a benign exposure of fragile tissue on the cervix, to a benign cervical polyp, to vaginal cancer even though that is rare in a young woman