Teen Pregnancy Advice?

I have just recently found out I am pregnant. I am 13 years old an nobody knows except me. My boyfriend just moved and I can't bare to tell him. I dont know how to tell anybody. Abortion is not an option because it is against my religon. I wouldnt want to put my baby up for adoption, but If my mom found out she would most likely make me. My brother has terminal cancer and he is the families concern at this time and I dont want tot ake attention away from him. Can anybody give me advice or tell me what my mom might say???