Well, it is normal to bleed some after having sex for the first time.
Now, since you say that your periods are irregular, maybe you were going to get it anyway. There's really no way to know.
Does this period seem like your normal ones? Or is it super light, like spotting?
yes. im irregular too and when i feel like it's coming and i have sex, when he pulls out it follows right away. We joke about it as his way of pulling my period with him. lol
Do you mean you bleed every time you have sex?