I talked about this on here before, this answers all your questions (and answers many more you DIDN'T want to know!):
I know i'm going to get clowned on for admitting this, but I didn't know it was abnormal until I was around 20. I actually had to learn about this from /b/ (4chan) of all places. It started with a thread on /b/ that was something along the lines of "best orgasm you ever had". I was confused because I didn't even know men had orgasms when they ejaculated because I never did. Also most of the time men don't say "orgasm", they just say that "nutted" or "came". Women had "orgasms" and guys just "came". That line of thinking made sense at the time.
A lot of people in that thread were confused by my replies (I was accusing people of pretending to be girls) someone brought up circumcision but at the time I shrugged it off because I knew it was a common thing and figured it was just inconsequential. Part of me thought everyone was just trolling and that guys didn't actually have orgasms. Maybe all those replies were OP? It was 4chan after all.
Not too long after I got into futanari hentai (thanks to be) and I was REALLY into it. The more content I absorbed, the more selective I became about the content. I developed a preference for futanari with testicles because I figured "how are they ejaculating without balls?". Sure you can make pretend they have inverted testicles, but I needed to see them. For whatever reason, this must be a minority opinion because 80 percent of futa is just penis and vagina with no balls. Anyway the point is I was focusing on the genitalia a lot for the first time.
I'd seen porn before this but I didn't watch much real porn, mostly just hentai. And most of the porn/hentai I watched before this was solo female (and even then i only cared about the boobs). So this was the first time I was focusing on genitalia/cocks. So in hentai, genitalia is "censored" but there's different levels of censorship. In videos they're censored the most, strongly pixelated. A lot of stand alone pics can be the same way, but in doujins the censorship is minimal. We're talking a thin black bar that's partially transparent. Nothing is left to the imagination. I noticed that ALL of them had that part, the glans. I didn't know what it was called at the time though. I knew "tip" and "head" but I thought that was just the end of the penis.
I'd seen this part of the penis before, but I didn't think much of it until that point. I figured it was just natural genetic variation. Sort of like with noses. Think of how much genetic variation there is with noses. Some are really flat, and some are really long. Some don't have much of a bridge, others have prominent dorsal humps. Some have a hanging columella and some are upturned. So I figured penises had this level of genetic variation. Some people had a glans, some didn't. Made sense at the time. And hey, my nose was way different from most other people's noses, so it made sense to have a penis way different too.
But it fascinated me seeing EVERY penis in futa hentai with this part. Is it something that all asians have but other races don't have as often? That made sense...asians have different eyelids and noses from other races, maybe their penises could be different too? Or maybe having this part of the penis was "ideal" and since they could draw penises any way they wanted, they'd always draw them with a glans? Or maybe I was mistaken and penises in real life didn't actually have this part. Maybe it was a hentai/anime thing. I mean, anime characters have green/blue/purple/pink hair, sometimes have golden or red irises, and sweat with a single large sweat drop. But still, I was getting worried I was genetically defective or something. And even if it wasn't maybe it was just really ugly, like my nose.
So eventually I made a thread about it on /b/ and everyone thought I was trolling, and I thought they were trolling. But again, someone brought up circumcision and implied that maybe mine was "messed up". I started looking up pictures of penises on google and all of them had a glans. I couldn't find a single penis that looked like mine and it made me worry.
I eventually asked my parents about this and they told me that something "minor" went wrong and they had to amputate the glans. My mother told me it was "just a little more skin that had to be removed". She was baffled and offended I was unhappy with this and basically called me ungrateful.
