Sex Help !!!

i just had sex for the first time, it was with my boyfriend and we used a condom but after we left he called me and asked if i’m on birth control, which i’m not. should i be worried that i’m pregnant? should i ask him if he finished? i’m most definitely not ready to have children. maybe i should’ve waited a lot longer to have sex if i was going to be stressed out like this. any advice ladies?