Is this considered child pornography?

[Name]

When I was stupid and 12, some girl on the Internet (didn't know her in real life) wanted to see my gentials, so I showed a picture of me with an erection under my underwear and (dumbass me) my face in it. Now about 2-3 years has passed, and I am becoming famous (not telling how to prevent someone like my parents reading this from finding out who I am) and my fear is that if the girl was a pedophile, then they might have posted it on the internet. Even if it was a girl, she could see my face and say "wait a sec, I have a pic of this guy with a boner" and post it / show it to other people.

My question is: Is this considered child porn? I have underwear on, so it's not technically nude (I was at least not stupid enough to show it bare) is it considered child p*rn? I'm really hoping so, because if it is somehow on the Internet then it cant be (would be illegal) posted where people can see it. Is it? I need someone like a lawyer to classify this, since nudity of children isn't illegal, however sexual pictures are. Is the erection sexual? If so, is it legal because the underwear is on?

The deffinition of child p*rn is sexual images of children under 18. This could mean any of the following:
1:sexual pictures of children naked (I'm not safe)

2 sexual pictures of children nude or not nude. (safe)

I was not touching my erection in the picture.

Thanks for the help, I will NEVER do anything like that again.

Also, would places like Facebook and twitter remove this?

Thanks, don't just say yes or no, say "yes it is child porn" "no it isn't child porn" or "yes it is illegal" "no it isnt illegal" etc