Am I sick?

Am I messed up for fapping to these?
Disclaimer!: I’m not attracted to actual underage girls, in any way.
There are just some hentai and ecchi pics that turn me on that happen to have characters depicted as underage.

Often when I fap to them I can’t do it without creating some absurd scenario, like the typical 3,000 yo deity in a younger body, or I’ve been drugged, or for Nezuko pics I pretend that she’s over 18, but using her shape-shifting to become smaller, etc.

I never search the loli tag, simply because many of the characters are depicted as gratuitously underage looking.
I’m not sure how to explain the difference, but there seems to be a line between what I’m posting here, and the bulk of loli pics online.
I think it might be the nubile body shape, and the face structure.

Is it natural to be turned on by these pictures? I’m not attracted by the fact that the character is underage, in fact I actively pretend they aren’t. But the expressions, the positions, the nubile body, all grab at my sexuality and I can’t help it.

Is this normal?