If one does not receive a call or letter this year and one really wants to attend the US Coast Guard Academy. My suggestion is to self-prepare at GMC or MMI. Remember, one cannot incur debt so find a way to self-prepare without incurring debt. If Admissions offers advice, make sure to listen to the advice, and take notes if necessary. It is not a guarantee one will not receive a Letter of Appointment after self-preparing but the Academy really appreciates reapplicants especially those that improve and keep productively busy during the year.
My DD was CGA waitlisted last year, listen to the advice she received, self-prepared herself over the year improving in all ways she could, reapplied, and received her Letter of Appointment during Early Action. She is currently finishing up self-preparation college, will have about a month off, and then off to Swab Summer she goes at the end of June with the Scholars she met while attending.