Most colleges have computer science programs and the difficulty range is huge. The ones considered the best are: Carnegie Mellon, Cornell, MIT, Stanford, Berkeley, Caltech. It will be a difficult major at most of those places. If you’re concerned that it might be too hard, then you might actually want to stay away from the ones which are considered the “best”, which usually also means the ones that are the hardest. At some other schools, it will be a much easier course, but will still prepare you for decent jobs. If you want to stay in Maine and go to a small school, the places you suggested are fine choices.

“Hard” is a very a subjective term. Some cannot do a subject if their life dependend on it. For others, it’s a breeze. And for the majority it’s somewhere in between. Anyways, have you taken higher level programming classes (i.e. not Basic)? If you like it, and are reasonably good then you’ll probably have an easier time adjusting to the demands. Good luck.