There are big differences between being charged with DUI and being charged with underage DUI. Perhaps most obvious, the BAC thresholds are different. If you are 21 or older, you are unlikely to be charged with DUI if you have a BAC of, say, 0.04, unless it has come in tandem with behaviors such as excessive speeding or highly-reckless driving.
Your first year in college can be exciting. For the first time in your life, you are on your own and in control of your destiny. Your teachers will be treating you like an adult, and you may have a job, bills and other responsibilities that reflect your transition to adulthood. For you and many other new college students in California, drinking is one of the many activities you participate in.