He told me that he forgot to pull out so we are really worried. I am a 15 year old young lady

Well um, me and my boyfriend just had unprotected sex on Saturday night. He told me that he forgot to pull out so we are really worried. I am a 15 year old young lady. Any advice would be greatly appreciated. After we had sex, like maybe an hour or so. I went to the bathroom and urinated. I just got my period last night but it was also a couple weeks late because like 3 weekends ago we had unprotected sex. I have been waiting for my period and i finally got it last night. It is like 2 weeks late. Please help. Im really scared to talk to my parents about it but i know i will have to. Please don't call me stupid or irresponsible for the actions i take. If i am pregnant i know i will be the best mom for my child. Me and my boyfriend really weren't planning on a baby at this time. We were gonna wait until after college and everything like that. Well like they say, Everything happens for a reason. I just really need help with this issue. My period is irregular and its not as heavy as it usually is. Is there any possibility that i could be pregnant? If you are wondering if i have done a HPT, No i haven't. Im too chicken to talk to my parents about this because i don't want them to flip out on me. Um, If you have any advice for me. Please imply it. Thank you all for you're kind and generious affection toward helping people like me. 

      xoxo