As a child, I grew two horns on my head.
Could you explain to me how you were able to grow horns?
I had a genetic defect. It kind stunk but I was able to have them removed.
It's good to have a nice imagination like that, but you shouldn't lie about such things. It's impossible for humans to grow horns.
I mean it's real! Seriously! Why won't you believe me?
I don't believe you because it's a lie, which isn't a thing you should do. Make believe and playing pretend is fine when one is a child, but as an adult it's time to move on from such ideas.