Steve, sounds like you have it all figured out already. Go for it!
One tip: don't wait too long for applying for the M-1 visa. I don't know about Ireland but the beginning of summer here in NL is the busiest time for the American embassy: All the Dutch students who passed their exams are then applying for their M-1 visas for their one-year college. Wait times of three months to get a visa interview are not that uncommon.