Am I just an idiot? Or a genius?

Ok so I'm a 20 year old man and for some reason i have never been interested in an intimate or romantic relationship with anyone. I want a girlfriend but it's so hard to get one with feeling like that. Luckily I'm not shy around girls, and have a very easy time making female friends, but they just want to be friends and seem to be much more "mature" than me. Anyway I met this really cool 8 year old girl and We're SO MUCH ALIKE! She's friendly like me, we love the same kinds of food, music, movies and she even plays the EXACT smae video games in her free time. Her favorite YouTube channels are mine, and she even has similar learning interests as me! Our favorite Minecraft mini game is the hide and seek modded mini map! On top of all that she thinks my jokes are HILARIOUS and she also is NOT interested in ROMANCE! Ok, she's 8 years old but I asked her what she thought about us getting married when she turned 18 and she smiled and said "ask me again when I'm an adult". I tell my friends I'm going to wait to get a girlfriend because I'm confident that I will marry this girl in 10 years, but my friends just say I'm an idiot. I would like to point out the reason I'm not interested in romance or intimacy is PROBABLY because I have Kallmann Syndrome. What do you think? Am I a genius for waiting for her or just an idiot?

Added (1). I'm not sure if her not having an interest in romance is due to the fact she is an 8 year old or just her personality. I hope it is a personality because when I marry her, we can date by playing Minecraft on the PC or hangin out at the park or watching a movie instead of going out for dinner and kissing like all those weirdos do. Yes I have Kallmann Syndrome and I still have the mentality of a 12 year old boy, but I'm not an idiot. Sexual intimacy for pleasure is evil in my opinion.

Ever heard of being a child predator? Even more importantly, something is seriously mentally askew in your brain if you at age 20 are pursuing a friendship with a child of 8. Your confidence in marrying this child when she turns 18 is highly illogical. If you can't stop interacting with this child, see a psychologist. Do this before someone reports you to the authorities or contacts child protective services to intervene. I would seriously wonder WTF this childs parents are doing while you are engaging in 'playtime' with this girl. They should be intervening here, putting a stop to this insanity before it gets out of hand. BTW, Kallmann is treatable and in no way does it affect the mental age in male or female patients. It only affects the reproductive and sexual aspects of the affected persons with side effects such as osteoporosis and infertility. So your excuses of having the mentality of a 12 year old are unfounded.

Chances are she will change her mind but if she doesn't good luck.