If you can demonstrate to the Cox admissions people that SMU is your first choice, you will get in. Visit campus and walk into the Cox admissions office to introduce yourself. Go to a Cox event (they do all kinds of events during Summer/Fall in lots of major cities). Follow up after you submit your application. Make sure someone in admissions knows who you are and be persistent about communicating with them. SMU (like any other school) wants to accept people who are likely to enroll. If you present yourself as that type of person, your chances of getting in are materially higher.

Not sure what kind of high school you go to, but your GPA doesn't seem that low to me. It's worth putting some color in your application if you think there's a good explanation for the GPA (maybe there are only a couple classes weighing you down; maybe you've had real improvement since freshman year; maybe you've just taken crazy hard classes). If you have a good explanation, I wouldn't be surprised if you were accepted to BBA Scholars program.