Sounds as if one someone brought out a friend, their friend ran the car in Novice, and the owner ran the car in STU. This is fairly common.
As Paul mentioned, I would just concentrate on getting faster each run and at the end of the day see how you did against the competition. Once you start getting consistant (all runs within at least a second), then I would start worrying about your competition.
I completely understand that you want to be competitive, believe me, I'm VERY competitive... I hate to lose

... but when you first start out you just need to get as much seat time as you can, learn your car and how it reacts, and try to get faster all the time. Being competitive will come with time. :-D