I think the guidance counselor at your school will be able to tell you if you have a good chance for admission to UT-Austin. Every counselor knows the answer for those in the top 6-7%, but after that it is more about the rigor of the school, the scores and grades.
I think your chances at GaTech are very low. It is a state school and they don’t admit many OOS students at all. Cal Poly? Maybe, but it is also a state school and will give no state grant money, SEOG, or federal work study money to OOS students. Do you need financial aid?