Absolutely, 14 and 15 year olds are children. I teach them, I was once one of them (a mere 15 years ago), and any adult who solicits sexually explicit conversations, pictures, and/or contact with them is a sexual predator. An adolescent does not have to be raped by an adult to be traumatized by sexual victimization by an adult, the mere fact he sent them pictures of himself and received pictures from them is enough to qualify him as a predator.
The law sees it that way too. That is why when he is convicted, he will become a felon and registered sex offender, as he should be.
SEXUAL PREDATOR-(Wikipedia)
The term "sexual predator" is often used to refer to a person who habitually seeks out sexual situations that are deemed exploitative.
However, in some states in the U.S., the term "sexual predator" is applied to anyone who has been convicted of certain crimes, regardless of whether or not there is a history of similar behavior.
In the state of Illinois, for instance, a person convicted of any sex crime against a minor is designated a sexual predator, no matter the nature of the crime (violent versus statutory, or perpetrated against a young child versus a teenager), and regardless of past behavior.
This has led to criticism that the term is being misused, or overused, and thus has lost its original meaning and effectiveness. (I AGREE).