Well first of all if she was sitting on your lap and felt it go in her through her clothes that's really hard she may have just felt it poke her. but as in getting pregnant no because you both had clothes on. if you did reach your peak during this time she may have felt your penis soften a little then get hard again as normal when this happens but she could not get pregnant unless there was actually contact between genitals. You have nothing to worry about. your girlfriend is not pregnant at. i would be scared to but your fine unless semen touched her genitals which is kinda hard to do through clothes