It is something a parent never expects. By now many parents are prepared for the idea that their son might reveal some day that he is gay. Lately some are perhaps setting aside a little bit of emotional reserve for the idea he'll reveal that he's actually a girl. But a pedophile? Never!
But it's happened. Here you are.
Rule one: Don't do anything hasty. Do not call the police. Do not tell your doctor or anyone at the school. Don't tell anyone at all, even trusted friends. Maybe later you'll want to do some of those things, but once you tell someone you can never "untell" them. There are often grave consequences to telling anyone, especially any professional. You want to think it through carefully.
So now you're not in any great hurry and you're trying to figure out what this means. If he really is a pedophile, it's not something anyone can change.
To get used to this, start with the best case. Maybe there's more to get used to as well, but let's take it one step at a time. This best case really is quite a common case.
Has my son abused children? No.
Is my son going to abuse children? No.
Is the only thing holding him back the fear he couldn't get away with it? No.
Does my son think that children would WANT to have sex with an adult or much older child? No.
Does my son want to change the laws so that it would be legal? No.
Does my son fantasize about raping children? No.
Has my son made friends with lots of other pedophiles? No.
Does my son think it's just fine to be a pedophile? No.
Is it going to get worse -- maybe losing self-control, unable to stop himself, unable to tell right from wrong? No.
Was he sexually abused when he was younger? No.
It is my fault he turned out like this? No.
If I'd done things differently could I have prevented it? No.
Does my son think about sex any time he's around a child? No.
Does he think about sex with his little sister (or brother, or niece, or nephew)? No.
So... Absorbing all that will take time. There's no guarantee all of those "no" answers apply in his case, but they might well, or all but one or two.
After going through what is NOT going on, what's left? What really IS going on?
Maybe you remember that when you got to a certain age, boys (or girls, depending on your preference) started looking really interesting. The right ones would make your heart beat faster and make you feel thrilled. This was a gut-level reaction. If you are straight the culture had told you it would happen, and your friends were going through the same thing. But it didn't happen because you thought it ought to happen or society said it should happen -- it just happened. This is how sexual attraction emerges in people. For your son it happened exactly the same way.
For some ordinary people this emerging attraction might be associated with a warmth between the legs or more obvious physical arousal, for others not. But even if the feelings were strong, you still had control over them. Maybe you got up the courage to approach one of these newly fascinating people, but you weren't seized by an uncontrollable desire to have sex with them. For your son it was the same.
Also notice that your emerging attraction did not contain within it the assumption that these interesting people were going to want to have sex with you. (You actually might not have wanted to have sex yet yourself, all things considered). That was a separate question. If you were straight maybe you figured it would be likely to happen in a few years, with the right partner -- one who you wanted and who wanted you. If you were gay or lesbian, there might be more anguish around it as you realized most of the people you liked just weren't attracted to your gender at all. Your son quite likely realized that not just most but ALL of the children he was attracted to would never be attracted to him in that way. He would never have sex with them. Quite likely the safety of children was never in doubt, even as his attraction flickered into existence and then became strong and clear. You are horrified by the prospect of teens or adults having sex with younger children. Quite likely he is just as horrified as you.
So far I've described the best case. The most common way the case might be worse is if your son has looked at child pornography. The simplest way to think about it is that your son had a strong sexual desire and was drawn to find ways to satisfy it that would not hurt anybody. Ordinary boys are drawn to find pornography involving women. Whether the women were exploited in making the material is unlikely to be of great concern to them. They are aware that looking at the video does not hurt the women. The exact same thing is likely true for your son. Society at large is horrified at child pornography, of course, and there are serious legal dangers. Children in child porn can be deeply harmed by it, and your son was likely deeply troubled by his fascination with it. But once you come to terms with the idea that an attraction to children emerged within your son through no fault of his own, there's nothing evil or monstrous there. A behavioral adjustment is required, but keep in mind all the ways that people hurt each other without meaning to, especially teenagers. With that in mind, it is an adolescent finding a way to satisfy sexual desire without hurting anyone.
There are of course other ways the situation could be worse. But start with the best case. One step at a time.