They are right, if you just go by the numbers, your chances are pretty slim. I actually used to know the numbers (I stumbled it in a discussion and hearing the study's results), well at least you survived August... (The one statistic I can remember is something like 80% of all relationships going to college break up in August). I also remember that out of that 20 percent that survive just the transition, fewer still will make it through college.
There are many reasons why it doesn't last, most people at 18 still don't even know what they are going to do. Even more is the fact most high relationship is meaningless, out of all the high school relationships, many are not together for anything else than status, others are never really attached, and for many other reasons that make a horrible foundation. Then there are even meaningful relationships that even they fall apart.
This is not saying no relationship survives (unlike at least the tone of some here), but don't expect it to. Hope that everything will hold together, but don't worry too much if it will survive, if it does, great, if it doesn't, that sucks, and quickly move on, for the odds was very low in the first place.
The one thing (though no one said it yet, but I bet someone will), is don't start cheating on her just because a poster says she will and you start expecting she will.