Is a pedophile interested in boys only?

Yes. If you are he, seek help. If you are not, do what you can. This is a dangerous situation for everyone involved.

If you are he, yes, absolutely get help. If you can't talk to your parents then maybe an aunt, uncle, school nurse, counselor, Bishop at church or someone you can confide in. If this is going on in your family or someone close you know of, you would be helping the situation out and may save a live so to speak by telling someone and helping this poor helpless person in this situation.