How do i decide on army medic (68 whiskey) or navy corpsman?

I'm 19 years old and already have my nremt EMT-B cert/license already. My asvab score was 92 so im deff. quallified. My recruiters call me crazy for wanting to become a medic but that's neither here nor there. I just want to get a better idea of any differences there are. I want to see combat and be on a line unit and i understand that is not guaranteed with either. But as far as the navy corpsman. If i want to go green side after my ait training with a (fmf) will i be able to get it? or is there a better chance for me to join army as a medic. (since they provide field training already). What are the odd as a navy corpsman that i could get greenside with the marines if i volunteer for it and let my commanding officers know i want it.