I did it for the first time but....

I had sex for the first time on Friday and its Tuesday now. My bf nd I were dumb nd didnt use protection. Now we didn't do it for a long time, we didnt even do it for a minute cause we didnt have protection. Can I still get pregnant even if he put it in for like what 30 seconds? I just really need someone to answer this for me. Plz don't judge over the question I'm just really want to know before I start to freak out even more.