First of all, congratulations on your acceptance.
As a parent of two kids who go to CU-Boulder and both have high grade point averages (one is Phi Beta Kappa), yes, there is partying. My kids have found a balance of getting a good education and partying. I can't compare it to other schools today, but compared to my own college experience back in the Stone Age when I went

, the presence of alcohol and drugs is really no more prevalant now than when it was then. And I went to a small, church-affiliated liberal arts college!!
Partying certainly doesn't dominate the CU's social scene, and there are many there who don't drink at all, or rarely do. It doesn't dominate my kids' lives either. There are simply too many other fun things to do in and around Boulder that you don't NEED to drink to have a great college experience there.
Actually, if you look at The Princeton Review's 2008 list of the Top 20 Party Schools, CU has gone down on the list to #13. Far better than the times when it was #1, or close to it.
I find it hard to believe that anyone could get "trashed" every night at any school and still be there after the first year. Do I think that there ARE people who do indeed behave this way? Yes, I do. And some of the do go to CU-Boulder. But you'll also find a few of them at nearly every college or university across the country. In any event, neither my daughter nor son have ever talked about that being the behavior of anyone they know of. It's an exaggeration, and a stereotype not based upon the way most people live in college.
I wish you the best of luck in your decision. CU-Boulder has been a good choice for my children and my husband and I have been happy with the quality of their education.