Hello, I am a sixteen year old girl. My boyfriend and I were playing around and his penis pushed against the outer lips of my vagina but may have brushed the inner lips. It is possible that pre-cum was on the tip.

It was the last day of my period. I have very irregular periods, usually spanning 2 months apart.

I don't know if this means anything:
After, I had swam for 2 hours in a chemically-treated pool.
My mother had difficulty conceiving.

I am wondering if I should take Plan B.