Ovulation can cause spotting, so that could be possible if you're not on any type of birth control. Bleeding during and after intercourse can be a sign of other things too - STD/STI's, cysts etc so if it starts to happen regularly then go see your doctor.
iT Did Thx's iWas Starting To Think iWas Spottin Because iWas Pregnat Since My Boyfriend Told Me Mayb It Was cux Yuhr ovalating Since it Was 15 Days After Ma Period
The thing is your body has to get used to sex. When you think about it, sex is pretty invasive, I mean, the skin around your vagina is literally stretched by your boyriend's penis and the tearing of the skin is what caused bleeding.
It is not period blood at all. Also if the encounter was a little bit rough and unlubricated, it is just trauma.
I mean if this is the first time, you have to get used to it.
The size of the penis matters too. If your boyfriend has a larger penis, it is more likely to cause trauma to your vagina.
Good luck. Not my normal topic, but hopefully it helped.