Being auto-admit at UT Austin means that you are in at a very strong university. I hope that this takes a lot of pressure off the process since you know you will have a great university to attend.
Otherwise you are a very strong candidate. Admissions at the top universities in the US is very difficult to predict. I think that you should pay close attention to be differences between the top schools, apply to the ones that will be the best fit for you, and see what happens.