Important questions

Grace

So this may seem like dumb questions but honestly I'm kinda stressing and worried. On Sunday my boyfriend and I decided to not use a condom. While he didn't finish he did pre cum. My questions are what's the chances of me getting pregnant and how long should it before I maybe take a pregnancy test? Yes I know we should have used protection. We did have a deep conversation before doing it.

Edit::: My periods are irregular so I don't think missed period would really help me here.