Is it normal that i feel different?

For as long as i can remember, i always had imaginary people in my head. They resemble traits, characteristics, and qualities that appeal to me and are ever changing, because things that i find interesting are constantly changing. They have names and everything, and it's weird that i say "they" when it's really this one girl that catches my attentions and there would be a group of people who don't have name or distinguishing traits because all the attention is on the girl. It's almost like a cartoon or tv show. I feel like it keeps me entertained. I usually imagine them while I'm listening to music, and i imagine a band playing, or if the music is hyper then they're doing something action-y. I would replay something i saw from TV over in my head, but with imaginary people doing them. So basically, it's a huge part of my life and i was wondering if I'm the only one who does this?