hey i am 24 year old. my girl friend is 20years old and she is virgin . this evening we had an outing during that we had some sexual game and i touched her private parts gently, on her vaginal entrance but did not enter my finger in to the vagina.. suddenly now at 11:55pm her cycle starts. just before 7days her cycle was ended. last time also after having this play her cycle started once again just after 2days of completion of her previous cycle. what is the reason of this . please help.