Visit both campuses and see which one suits you better. Mines is very good to expose you to engineering and CS and has smaller class sizes, with some very good teaching faculty. Mines also offers the tougher core program,
see this website:
https://catalog.mines.edu/undergraduate/undergraduateinformation/distributedcore/
Lockheed Martin in Littleton, hires a lot of Mines Mechanical engineers and CS majors.
CU has more majors, in case you change your mind, and more research faculty doing cutting edge work in CS
and Aerospace engineering, and LASP right near campus for research and jobs!
They do try to get undergrads involved.
(The CU Engineering students have a little lower test scores than Mines students.
Both have a good reputation. )
CU Boulder has the Lab for Atmospheric and Space Physics , LASP, near campus and aerospace students work there, if you have good grades and pursue a research option–
https://phys.org/news/2017-12-cu-boulder-solar-instruments-space.html
http://lasp.colorado.edu/home/
CU Boulder just hired 15 new computer science faculty: (some are not yet in residence).
https://www.colorado.edu/cs/2017/10/03/meet-our-15-new-faculty-members
Computer science is crowded at both schools right now and all over the country. its a good idea
to take CS classes even if you major in some other branch of engineering.