This is one of the few times on CC where you really seemed to undersell yourself in the OP. In reading your responses to questions, your rigor is significantly better than you indicated. Be sure your applications don’t reflect the same type of underselling - not saying to brag, but accurately reflect what you’ve accomplished.
Are you completing the full IB diploma? I ask as some schools do value it more than others, and CMU is one. It’s also very much a fit school, be sure you visit if you haven’t already. Some of the others that like IB and have mechanical engineering are Purdue, University of Denver, University of Washington, RPI, University of Rochester, Lehigh, Case Western, Washington University St. Louis, and Rice. Many of these are a much better fit than a Swarthmore or Pomona if you want to be an engineer. CU Boulder has a great aero program and lots of California’s who didn’t end up in the UC they wanted. Good luck.