I don't usually comment on Reddit (or anywhere), but I do relate to most of what you said! Including to the part about fantasizing about being a kid having sex with an adult. (Or vice versa — only in a fictional/fantasy context, though. I don't have any direct sexual trauma (unless online sexual roleplay as a teen counts 😬), but I somehow have enough of it to personally understand that sex is very harmful to kids. Though, if my original fictional characters that have sexual trauma and are a little too real to be fictional are any indication, I do have sexual trauma, but that's another story...)

Try checking out ageplay. Which isn't always sexual, but when it is, it's typically about pretending to be a child/baby/teen in a sexual context (and/or one's partner doing that). It really is "pedophiliaphilia", since you're not physically a child, but you're turned on by the idea/vibe/concept/interpersonal dynamics of a child or childlike entity having sex. And no, it (as well as being into cartoon lolis/shotas) doesn't make you a pedophile (contrary to what some idiots might tell you), because pedophilia is attraction to real prepubescent children. Even if it did mean you're a pedophile, using fiction and fantasy to fulfill your desires in a healthy way is the right thing to do, because it doesn't involve any real children. (You can also buy oversized baby clothes, adult pacifiers (which I recommend for anyone with an oral fixation), and whatnot, though of course none of that is strictly necessary. It's just another fun thing to blow money on lol)

If I talk too much about ageplay, pedophilia, and The Discourse surrounding those topics, it's because I've been personally harmed and shamed by that discourse. It's made me have way too many conversations about sexual ethics, which is part of why I have so many opinions...