Can u tell if your prgenant within the first week of having sexual intercourse?

From a young naive young lady.I have recently become sexually active, and I’m kind of nervous about the whole thing. My mum doesn’t know. My question is this. Is there a way to tell if you’re pregnant within the first week of having intercourse? My boyfriend always prematurely ejaculates, but we use condom every time. I’m not on any form of contraception, though I’d like to be. I’m worried his semen could have gotten inside me and I could get pregnant.