Like @rb924119 mentioned, you're ahead of the ball game just be being on a weather blog. I don't know how your class schedule will go exactly. On occasion, if you pass your advanced math and physics courses in HS, Millersville can bump you straight into sophomore level courses for your freshman year. If not, you take the route most of us take. Freshman year, the only interaction is a general course that introduces you to various parts of the department. It's called "freshman seminar". Sophomore year includes "Intro to Meteorology", introducing you to topics like pressure gradient, hydrostatic equation, and the like. That's a fall course, then spring sophomore year has Cloud Physics & Radiative Transfer (two separate courses, when I went through it was one course called Physical Meteorology).
Anyways, that's a start. Walker Circulation and ENSO get discussed in Climate Dynamics, senior level course. MU has 1 forecasting class, that's Advanced Forecasting senior year. If you want to do forecasting freshman-senior years, participate in the forecasting competition WxChallenge & forecasting activity for MU.
Job wise - it's competitive...really the best bet is getting an internship and being offered a job. Also networking is important (I stink at this). One of the good things about MU is the Speaker Series we have each year, where we bring in speakers from all over the country. Accuweather, NWS, Air Force Hurricane Hunters, and Mars were some organizations who visited MU last year. If you want NWS of federal track, my best advice is to find a current employee there (if you have a local office, befriending them is great) and having them assist you and give you advice. If you want something specific private company wise, again, reach out. Or ask around and see if you can't get connected with someone. A personal example is I met the WCM from my local NWS office and she assisted me on my resume, gave me a tour of the NWS office and job shadowing, and she helped connect me with others who were glad to assist.
Honestly you're probably going to be one of the more weather aware students if you attend MU. Don't let that go to your head, just keep it in mind. Also, be sure to find the correct classmates to study with - the program (like a lot of meteorology and heavy math oriented programs in the country) has a 50% or greater drop out rate. That's mainly students who cannot get past Calculus I or II.