Hmm. I don’t have specific knowledge of track and field (so I can’t say if your times are competitive), but I do have experience of a different sport for D-III athletics at Pomona/CMC/etc.
To be perfectly honest, the coach is likely not interested. CMC takes its athletic teams very seriously, so I’d assume the coaches actively recruit. The biggest problem is that you don’t really have a track record; from what it sounds like, you’ve participated in significantly fewer events than other athletes, thus immediately raising a red flag for a coach.
Your times may also be uncompetitive––check past results and compare your times to current CMS athletes. If your times are competitive (immediately craft a resume/make a video/get a letter from your coach/etc…prove yourself), then I’d want to know your standardized testing/GPA. Is your GPA 3.8+ and testing 2100/32+? Keep in mind that since your record is shallower than most, your scores need to be very impressive to be deemed competitive by the coach. A little bit slower and the coach will not consider someone who has only participated in the sport for under a year. If your time are not competitive, then that’s why the coach isn’t responding. (Rarely does a coach ever send a “we are not interested in recruiting you email.”) I’d then recommend that you target schools with less competitive athletic teams (CMS is one of the best DIII, numerous other DIII schools are significantly easier to play sports for.)
Something else to consider: most athletes, even in DIII, want to continue to pursue their sport competitively and are not simply using it as a way to gain admission to a selective institution. Be sure that you fall in the group that wants to continue with the sport.
Are you being recruited anywhere else?