I am a 18 yr old boy and i touched my penis with my girlfriend, can she be pregnant. i am not sure of theprecum , and her cycle is about to start ?

Depends on "touched": Pregnancies require sperm. If worried, a home urine pregnancy test gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If a woman gets her normal regular period, then she is not pregnant.