How does choosing major works?

I am currently having a hard time
trying to decide which Cockrell Majors I want to apply
I am considering Aerospace, Elec, Chem, Mech

What I am curious about is that, if I get in to for example ChemE. Than would I be garunteed as a ChemE student?

Or is ChemE just a “preference” and it really depends on my performance after freshmen year?( like, can I change in to other majors such a PetE if I did good?)

If you are accepted as a ChemE student, you are placed in the ChemE program right away. You have to maintain a minimum GPA within your major (I think the minimum is 2.0) in order to not be removed from the program. If you get below that in your first semester, they can give you a warning and tell you that you need to satisfy the requirement by the next semester.

Once you get to your second or third year, you will be choosing a concentration within your major (a specialization). You are still ChemE but you can pick which topics you want to go more in-depth on.

If you are a UT student and you want to change your major while staying at UT, that is called an Internal transfer. You can find information on internally transferring to another engineering major here: http://www.engr.utexas.edu/undergraduate/admissions/changeofmajor

Engineering in general is hard to transfer into but some engineering majors are easier to transfer into than others. ChemE and PetE are extremely difficult to internally transfer into so make sure you do your research and try your best to make the best informed decision you can.