Beware of 3/2 engineering programs. You should ask about them on the engineering forum, but I’ll give you a synopsis. Admission to the 2 isn’t typically guaranteed. Financial aid at the 2 isn’t typically guaranteed. Most students don’t want to give up their senior year at their 3 institution. You’ll spend an extra year. Transition to the two, especially to a school like Columbia or particularly Caltech, can be traumatic, as the students you’ll join have had two years of intense rigor already. All in all, the success rate is not high. There are lots of good schools that meet your needs without the risk.