the first guy I had sex with, we dated for 3 years. It was probably the most boring sex ever. She's had no experience other than you, so she's going to be shy in bed. It took me a few years and a few partners to actually figure out what was going on, what I really liked, how I liked it, what guys liked, etc.
I NEVER even considered anal with my first. It was totally out of the question. doggy style seemed kinky at the time. lol She just has to be TOTALLY comfortable in bed to try anything new. Don't push it with her, take it slow, and talk to her about it. tell her it's something you REALLY want to try with her because it's just that more intimate, and you want that with her. Then tell her if she doesn't like it, then you won't bother her again about it.
Make it about her in bed, and you'll eventually get anything you want
Make her feel special, that you love her, and that you don't just want a quick fuck out of her whenever you have the urge. The last thing she wants to feel, is cheap... you'll NEVER get anything else out of her if she does.
And when you do... invest in an economy size of lube, and make sure she's COMPLETELY comfortable, otherwise she'll tighten up, and it will hurt like a MOTHER FUCKER, and you may as well join the priesthood. haha