Congratulations on finding a girl with great hair!

My best advice to you would be not to tell her that you have a "hair fetish" because then she might think you only want her for her hair. You don't have to label it.

Instead, just casually let her know what you think about her hair. How beautiful it is. How soft it is. How good it feels against your skin. She'll see how excited you are by her and her hair, and you can work into hairjobs, etc. Mix these in with compliments

Also, maybe avoid playing with her hair while she's asleep, at least until you get to know her better and make sure she's okay with that. If she thinks you're being weird with her hair, that might poison the relationship before she can fully understand your affection for her.

Finally, don't worry about posting pictures of her hair here -- at least not right away. Maybe she'll like having pictures taken of her hair, and you can post them later. Don't risk doing anything to lose this girl!