Most mormon girls look at guys like you as a project and that they have a lifetime to work on the project. I married a non-member over 20 years ago. It may not seem like a big deal now, but eventually it will probably surface that at best, the church impacts and influences her behavior in almost every area, at worst, it dictates it. If all you are looking for is some non-serious dates to have a good time, you should be fine. Plan on knowing their religion better than they do at all times. At parties, they drink soda and play board games. Why prophets are awesome. It is nice to hear that I am not alone, and that we can do it. If it's the latter then you may need to be more direct and take initiative. That doesn't get better unless you humble yourself, either -- admit you might be wrong.
Do you drink alcohol. Might be worth working through the missionary lessons and CES letter to see if they can agree at least to disagree. Learn all you can.
Do you drink alcohol. A good man is not defined by his religion and a great marriage is not defined by where it takes place. There's a reason so many Utahns are on anti depressants and anti anxiety meds. She likely believes that her time as a missionary was preparation for marriage.
And even then it will put Huge stress on it and on you for the rest of your life. But of course this does not mean that mixed religion children cannot grow up to be LDS stalwarts. I don't really care if she's religious or not, unless she brings it up all the time or tries to convert me. You should also be willing to date other people. BUT it could easily have gone the other way. Do you and your girlfriend have any kind of plan for how you're going to manage your relationship while you're both in residency. And you know what. If you have tended to straddle the line between light and dark in the past, or have been a partier, expect to make some changes for this relationship, and expect certain things from your new crush.