Is it normal to love a girl that is not real?

Ok so here's the thing:
I sometimes dream of a particular girl. I feel like I know her well, I even hace a crush on her (kinda). But the weird part is that I DON'T know her, at all, in the real world! I don't even know someone like her, she is not a celebrity or linked with one, she is not from a movie, nor a videogame, nor a mythology...

I feel like I know her from a long time ago, and In the dreams where I encounter her, I don't think of asking her who she is because I don't even think of it, it's like, normal, in the dreams.

Well I'd like to know if it's considerate normal and if you happen to have similar dreams, tell me in the comments!