If ur not ready to be a mom make him wear a condom or go get free b.c. from the clinic if ur under age. I knew a few girls who got pregnant with the pulling out method . Be safe.
If you are irregular then it is hard to calculate when you are ovulating but I doubt you are pregnant. Pulling out is not a good method of birth control, it leaves too much to chance because some sperm can come out before the rest. You can take a early response test that will show you in a week or two. If I were you I would not do anything unless you miss your period for more than three months and have other signs of pregnancy i.e. nausea, vomiting, sore breast ect. I only say three months because you are irregular. Hope things come out well for you.