Make sure everyone involved is a couple, or at least is paired with someone. Looking back, I can say that when I received this answer to my prayers, I was at one of the most spiritually high moments of my life. He may never want anything to do with Mormons or the church again. Dating in your teenage years will help you learn the kinds of things you value in another person. Juggle them with a working wife, a housewife with children and things become difficult. You will only have a happy relationship if either you both believe in the Mormon Church, or both do not believe.
And some will do that. She will probably feel persecuted and attacked if you try. Even if you are looking towards marriage, it can be better to hold off on more serious activities until a couple of dates to make sure you both feel the relationship is moving in the right direction. To her, if you don't marry in the temple, she will probably do it after you die anyway. Their son grew up to become a temple president. How convenient for him. Mormonism is a lot more controlling and has a lot more downsides. The brethren have taught that there is an ideal pattern for marriage. If so, you have a chance. I know residency is particularly bad, but what about when he finishes that.
To others making this consideration, I would certainly suggest that you converse with your Father in Heaven about this important choice. Mormons have separate congregations for young single adults, which is very convenient. The most damning information is in the footnotes of the essays.
Mormonism and Non-Mormonism don't link to future lives. A lot of people will tell you to run but if she is in her late 20s most Mormon guys her age are married. We met when I was 19 and have been together only the past 4 years but the love has never died. Even after being in a relationship I have to take all the decision alone. Go on dates on days other than Sunday. And occasionally I have queried the wisdom of that choice. Can you live your whole life with a husband you doesnt or never will believe in the mormon church. This has been a good distraction when she's doing awkward shifts but coordinating time together can be difficult. Don't get her hopes up too much - in return ask her to do something to research your views. I think the most important thing is to bring up the issues as questions rather than points as why she's wrong.