that maybe shes underage of getting pregnant by an older boy
If you're in the US, no. Getting your girlfriend pregnant does not give you any adult rights. If Mom and Dad say you have to move, then you do.
NO!
in the state of illinois can a 18 year old boy get in trouble for getting a 15 year old girl pregnant even if they are in a relationship
Any time they have sex.
Yes, you can get in trouble for getting someone pregnant. It may not be criminal, but there are going to be reprocussions.
ANY girl regardless of what she is can get pregnant if she has sex with a boy if she has started puberty.
You can go to jail for that!!
If you are a boy who is a virgin, it doesn't make any difference in your chances of getting a girl pregnant. If you are old enough to ejaculate (if you have semen come out when you masturbate of have a wet dream) you can get a girl pregnant. And you don't have to put it in her, either. A little sperm from the tip of your penis on the outside of her vagina could get her pregnant. If you are a virgin, the best thing for you to do is stay that way until you find the right girl and marry her.
No it is not possible biologically for a human to impregnate any other species or viceversa. So to answer your question simply, "No a boy cannot get a female pony (mare) pregnant."
Yes. On top of getting pregnant, the 23 yo woman would get arrested for Statuatory Rape of the 15 yo boy (even the sex was consensual).
The girl may be charged with statutory rape, even if the boy consented.