Some schools have scholarships for returning students. There are also some (highly competitive) national scholarships for certain STEM majors. Look at your school website to see if any of these might be possible in the future.
Also look at the DOD SMART scholarship for STEM. It is similar to ROTC, but DOD instead of a military branch. You get scholarship money for college and summer job, then you work for DOD for a fixed amount of time, depending on when you are accepted (work for 1.5 years for each year of college they cover). This is a competitive program too - 2017 had 14% acceptance rate.