Is it normal that i have conversations in my head?

Hi, so I'll just get straight to the point here. I have conversations with people in my head. These voices started to appear when I was 4. I was born an only child, so I know what it's like to have imaginary friends and go on imaginary adventures with myself, but these conversations are different in a way. They seem so real and genuine to me, like when I was pretending to talk to someone else in an imaginary game, I knew it was all fake, but when I'm taking to someone in my head, I honestly can't tell as if they're real people, or if my mind's playing tricks on me. What makes this so confusing to me is that the voices in my head belong to a specific person, but I haven't seen them ever in my whole life. It's sort of like the voices belong to two specific people, one being a boy much younger than me, maybe around 12-ish (I know, it does sound weird having a twelve year old boy inside your head) and this boy shouts out in my head random things that catch me off guard, like once when I was relaxing, this boy just randomly shouts out, "I like frosted sprinkled doughnuts!". Don't ask me, ask the voices inside my head. The other voice belongs to a girl that's maybe in her late teens. She's usually the moral person in the conversations inside my head and whenever the boy screams something random, she sometimes scolds him. We sometimes have conversations together when I'm not doing anything, and we talk from things such as school, our social lifes, etc. Apparently the girl goes to a college somewhere in the southern United States (she has a twinge of southern in her voice), maybe Alabama or Mississippi, she's never specific when it comes to describing her surroundings. The boy claims to live in Canada, I think around the Vancouver area, because he says that he lives near the ocean, but he never goes swimming there.
It would be great to have feedback on this situation of mine and so far, whenever I tell someone about this, they look at me like I'm a crazy person, so please respond to this and give me hope that I'm not a lunatic, thanks!