Where I went to law school, teens having sex with one another was not considered illegal. Even if one turned 18, if they were close in age, charges were not pursued, although some parents waited with bated breath for that day. In the nether regions of that state the standards didn't seem to ever hold up. I recall reporting a 36 year old who had impregnated a 15 year old to Children's Services. The response from the work on the phone, 'yeah, so?'
If you are looking for distinctions, then understand that 'pedophilia' is a psychiatric diagnosis. The legal issue is 'rape of a child' or 'statutory rape' depending on the age of the child.