aw i'm sorrry, but I'm glad that you realize that she doesn't appreciate you. Maybe it's not going to work out, even later. She does sound like she has some growing up to do.
I think by saying that she hasn't experienced life, she means she doesn't think she's dated enough or that she hadn't done what she wants with her life yet to settle down.
How she feels is understandable, it happens sometimes. She should've told you this before hurting you though.
People grow apart and maybe even out of love.
She's missing out though, because you are working really hard to work it out.. and i've learned that usually it's women that do this, not men. Not many men go through hell for a girl.