Congratulations on your achievements.
You seem like you would be a great Questbridge applicant, but not all partner schools offer engineering, take a look here: https://www.questbridge.org/
Do you have a guidance counselor at school who is helping you with the college admissions process?
Are there any in-state schools where you would be able to commute? Even with the UT Austin Advance Commitment, you will have to pay for room and board, health insurance, travel to and from campus, and incidentals.
Did you take the PSAT? If so, are you a national merit semi-finalist?