Liking someone unexpected.. sort of?

So there's an older woman in my class.
(We're both lesbians.)
I'm Under 18 and she's 40.
She's not an attractive lesbian.
She's got a hilarious personality, she's awesome in fact.
She gave me a hug good-bye today and we are always having a laugh together.
Appearance wise, she's.. Your normal older lesbian looking woman.
I have beautiful girls who have wanted me or who I could have kept but I just didn't feel it.
I don't have a crush on this older woman..
But sexually I feel like..
I'd rather do that with her than any of the attractive girls my own age.
I do fantasize about it, I'll admit..

Is this normal?!