Yes. Even if the breathalyzer test shows your blood alcohol level is below .08, you can still be arrested and charged with DUI if the officer believed the alcohol in your system impaired your ability to drive.
If you are under 21 it is illegal to drive if your blood alcohol level is .02 or higher. This is known as a “baby DUI,” which results in a fine of up to $500, a 90 suspension of your driver’s license, and completion of a chemical dependency education course.
However, most police officers in Bozeman will charge anyone drinking and driving (above .08) with a DUI, regardless of whether you are under the age of 21.