Can a virgin to experience uterine prolapse?

Yes, it's possible: Although uterine prolapse is more common in patients who have delivered multiple children vaginally, it can occur in virgins who perform a lot of "straining" tasks that require an increase in abdominal pressure pushing the uterus downward until the supporting ligaments "relax". Gravity is "the enemy" of such a uterus.

Yes: Although vaginal childbirth is a big risk factor for prolapse, there are other risk factors such as chronic straining from constipation, chronic coughing, or heavy work or anything that increases intra-abdominal pressure. There may be genetic predisposition also.