I wouldn’t let the difference in median salaries sway your choice – I would think a lot of that is self-selection by the student body. Rather than assume, I took a quick look at HolyCross’ job data, and its 2016 graduate report shows that health care and financial services account for about 1/3 of the graduating class’ jobs, with another 9% attributable to careers in education. For its class of '16, Grinnell reports that computing/information systems and education make up about 1/3 of its job placements, and another 13% in health care.
From what you describe about your academic interests, Grinnell sounds like a great fit. Grinnell alums do very well – as I’d say to any college student, attending any college, start working with career services early, schedule meetings this fall, meet your career advising staff, use the college’s resources to help find internships etc.
Congrats, and good luck!