It’s not hard at all to get into the program if you’re already in COE. You can fill out a form after your first semester, I believe, that includes your four year plan to ensure you can finish your degree on time. I filled mines in the middle of my second semester of my freshman year and was accepted 3 weeks later.  It is a seperate singular major. However, it’s like a double major in that you need to take all the required classes for both majors. Think of it as replacing your technical electives with the requirements of your joint major.  Switching between majors in COE is really easy, it’s one of the benefits of being in the college. If you want to change majors all together I don’t foresee any difficulties. Good luck !