Could my girlfriend be pregnant?

Hey guys. So plan and simple i have been very nervous for both myself and my girlfriend. Her last period was a little early and her most recent one has yet to pop up. As of right now it would be categroized as late not yet missed. We do not par take in any form of intercourse but we rub our bodies together with clothing on and only once recently have i ejaculated inside my boxers and jeans with her on top wearing her whole attire. She does not have any other symptoms of pregnancy but regardless I am still very nervous. Could she at all be pregnant? And if not what may be the reason for te early and then late period? Thank you so much guys. Please somebody help me!??!