Have you calculated your MCA points? Post #52. http://talk.collegeconfidential.com/cal-poly-san-luis-obispo/1694769-confused-about-mca-score-p4.html
Your ACT is very competitive but your GPA is well below the averages for the College of Business (Econ) of 4.12 and College of Liberal Arts of 4.04 (Sociology).
Target projection acceptance rates for Sociology (24%) and Econ (16%).
I think your GPA will be an issue make SLO more of a Reach than a Match.
Submitting your application early does not give you any advantage. Make sure you have some solid Match and Safety schools on your list and best of luck.