You must have sex to get pregnant. Sperm need liquid to swim through. It's the same logic you use when you are chilling on the beach, unworried about a shark crawling out of the water and eating you.
A woman can get pregnant from having unprotected vaginal sex before her period, but the chances are not as good as they would be mid cycle.
I think it would be REALLY wise for both of you to go to the doctor, school nurse, or planned parenthood to learn more about sex ed. You are engaging in an adult activity with adult consequences. You need to get informed to make good, safe , smart decisions.
can you please elaborate a bit? i mean... how and all?