As far as the current rules go, if you're in top ten percent, you get into A&M automatically. I'm not sure if that's dropping down to 8% next year or not though, so you might want to check that out.
You get automatic admittance into any public state university in Texas, however, you still have to apply for your department.
You can get into A&M and get rejected from the Dwight College of Engineering in general, or the department of Mechanical Engineering in specific, for example.
In which case, you'd have to enter into another major, or enter into General Studies, and apply for transfer into the department/major you want later.
If your SAT scores are not high enough, or if something else happens, the engineering departments might tell you "Hey, we like you. But we don't have enough room for you because there are other students that we are giving priority to. Come in as General Studies, keep your grades up, and apply for transfer into our department next semester", which is totally possible.
These are the change of major requirements at A&M:
http://gest.tamu.edu/Main/gpr.pdf
Notice the engineering requirements:
ESSAP - Changing Majors
Biomedical Engineering is the most difficult and competitive major at A&M to get into, and there are very limited spots available.
After that, in terms of most difficult to least difficult to transfer into (generally):
-Mechanical, Aerospace, Civil, and Electrical Engineering.
-Chemical, Computer Science, Ocean, Petroleum, Nuclear, and Radiological Health Engineering.
-Industrial Distribution and Industrial Engineering.
-Biological and Agricultural Engineering, and University Studies Degree
Area of Concentration - Telecommunications Technology
i'll keep that in mind, if i don't make it to MIT
Since you're just in Algebra II and your Math SAT scores are not in the 730-800 range, I'd almost eliminate MIT as a possibility. They don't accept students, regardless of how awesome/bright you are, if you can't handle rigorous calculus and calculus-based physics upon entering in as a freshman in the Fall. Because they don't want to accept people who will just fail out.
Northeastern University's co-op program is regularly ranked best in the country.
Now let's not start bragging...:>
http://online.wsj.com/article/SB10001424052748704554104575435563989873060.html
http://online.wsj.com/article/SB10001424052748704358904575477643369663352.html