No period for 2 months...

I'm 15, I got my first period when I was 11, and it has rarely been on time. Sometimes it'd be a few days late and sometimes even 1-3 weeks. Once I missed a period and got my period 2 weeks after that skipped period. Now it has happened again, the last time I had it on the 15th of February, I've skipped one and now I should be getting my 2nd period since then. I have a boyfriend, we have never had sex, we have done other things but is there any possibility I could be pregnant from somehow having semen near my vagina but not inside.