Wondering

Stupid question.. but if you get off your period and 3 days after you have unprotected sex and he cums inside you, what’s the possibility of getting pregnant? I know ovulation is the main goal lol. But for a young girl is that a possibility? Or does it always have to be during ovulation or around it. Again I know it’s a stupid question but then again I have no clue tbh how it all works. Lol