I can second this, as a lifelong utahn this is why I simply have a "no mormons" policy for dating. Being married and raising a family can be very difficult if the two of you disagree about important issues like religion.
Love quotes for dating to say what will impact your girl most - but girk your best LDS. The important part of finding a partner to marry does not, in my opinion, revolve around whether or not you are of the same religion. It's also possible that deep down she's like many of us here, and her shelf will break and she'll want out.