And I believe you’re thinking of this in the wrong way. Those colleges will expect some familiarity with engineeering, to be a competitive applicant. Because of the high level of class peers at those colleges, the work might be crushing. Those scores don’t match other applicants.
You do not need the crazy competitive world of those colleges, to get to a med school program, somewhere. At those, they tend to “weed out” all but a much smaller number of students they will recommend for med school.
You’d be better off at a smaller college where they offer the support and encouragement- one of those that does offer financial aid.
As for astrophysics- it sounds alluring. The reality is, again, you need the right background. Pick a college where you can thrive in their real environment (not just their reputation or ranking.) You can always take side courses at a local U or get started via some of the online (often free) courses, then build at the right pace.
You need more than ideas or hopes. You need a reasonable, feasible path to get there.