Can a virgin girl get pregnant when pre-cum touches her vagina?

YES!!!: There are thousands of sperm in that precum, and young sperm are excellent swimmers! The sperm can absolutely swim inside the vagina and up to the uterus and cause pregnancy. This is also the reason why the "pull-out" method of birth control often fails. In both these situations there is enough sperm close enough to the "target" to cause a pregnancy!!

Potentially: There is potential for pregnancy if sperm is deposited at the introitus (opening of vagina) or within the vagina. If not ready for pregnancy – use protection every time.