I’m far from an expert on Cal Poly or engineering, but I can say that Cal Poly SLO is notoriously difficult to get into for engineering, especially for those who live outside of the area. I feel your GPA could be be a hindrance to Cal Poly SLO for engineering.
The average GPA for Cal Poly’s engineering is 3.55, which you aren’t too far under, but they also only accepted just under 12% of all applicants for this fall.