i’ve actually been thinking along the same line. you want to start with the gmat. the score you get will condition for the most part the schools you will be able to apply/get admitted to.
at the same time start researching what schools have the programs you are most interested in. i know quite a few ppl from different backgrounds that have gone the mba route and most suggest doing a more general curriculum then specializing as you will be more “marketable”.
let me know how it goes.