A 23-year-old Christian woman wrote to ask what I thought about her dating a non-Christian. "It's a problem plaguing my life," she wrote. "This man treats me like a queen. I just want to talk to him all the time and blah blah gush gush so forth. The problem is that he is not a Christian, and my family ... well, they are, and don't like this relationship of mine one little bit. As far as they're concerned, any non-Christian man is a rapist or murderer waiting to happen. I love my family; I love my boyfriend. My question is: Is it right for me to date a non-Christian? And if I do, how do I deal with others who make clear that they think my doing so is wrong?"
Let me address your second question first. There are only two kinds of people who can condemn you or anything you do: People you care about, and people you don't. You only care about what people in the latter group think. When you're doing something to which someone to whom you're close takes exception, talk to that person about it. Work out your feelings about it together. If that person loves you, of course they'll want what's best for you. If they don't love you---or, as is more usual, if they love you more the more you fit their idea of who you should be---well, this might be a time for you to explore what that means relative to your overall relationship with that person.
As to whether or not it's okay for you to date a non-Christian: Of course it is. It's just dating, which is all about what amounts to noncommittal exploration. But it doesn't sound like you're just dating this guy. It sounds like you're in love with him. And when a 23-year-old woman is in love with a man, it usually means she's thinking about that man as a potential husband. And marrying someone who doesn't share your religious faith is one heck of a big problem.
You can't really be with someone who doesn't share your most profound, intimate, and vital convictions. Because it means the most important part of you---a huge part of you, the part of you that most wholly makes you you---is beyond their understanding, their grasp, their appreciation. That doesn't make them stupid or shallow or mean-spirited. But it does mean they exist in a whole other world than you. It means their core values are categorically different than yours. It means they can't really get you. It means they don't grasp what makes you tick, motivates you, inspires you, moves you in the deepest way anyone can be moved. It's like me trying to fully empathize with the reality of an aardvark. I can imagine what it's like to be an aardvark. I can sympathize with the problems an aardvark might be having. I can even love an aardvark. But I'll never fully understand what it's like to be an aardvark. It's just ... a different order of existence.
Different consciousness. Different drives. Different needs. Different values. Different reality.
You can marry someone who doesn't share your religious convictions. But doing so means going to bed every night with someone whom you know doesn't really know you. And you may have your own reasons for why, in fact, that works for you. But in the end, it won't work for you. It can't. We all need spouses who really and truly get us---who know and love the very core of who we are. Sooner or later, anything less than that will leave us restless, angry, and looking for a way out.
The key to a truly happy marriage lies in gradually, over the years, revealing to your spouse deeper and deeper truths about who you are. We are barely designed to know who we really are, much less to share that truth with another person. But marriage creates the psychological and spiritual context for the miraculous, deeply interactive process by which each partner discovers and reveals to the other everything they know and learn about ourselves---and by which, in their turn, their partners absorb that input, lovingly integrating it into their worldview, into their self-identity. And thus does marriage, in a very real sense, make one life out of two.
A Christian marrying a non-Christian is entering a relationship destined to fall short of its potential. (Unless the non-Christian undergoes the most radical personal change possible, and the hope of that happening is no basis for a marriage.) A Christian can share a good deal of themselves with someone who doesn't share their faith---but they sure can't share all of themselves. They can't even share the best part of themselves. If they try---if a Christian begins to try to share the real stuff about themselves with their non-believing spouse---all the spouse can do, finally, is shrug, and say that they just don't get it.
Which leaves the Christian spouse with exactly two choices: File for divorce, or continue on, married and alone.