No pic and kegels are the key to a tight pussy
My lady was the same way 7 years ago. She felt that her asshole wasn't a sexy part of her body. I just kept telling her that her ass was sexy. She did try anal 7 years ago but it hurt to much. So I let it drop for a few years, then I started just rubbing her little hole while fucking her pussy. I encouraged her to play with her own ass as much as she could.
My advice is:
1 be patient
2 do anything and everything to boost her self-esteem
3 find a way to link anal to something she finds pleasurable
4 be patient
5 like buffalo28 said if she says slow, go slow
Good Luck and Happy Humping