Sorry for the confusion, I was always joining the Army. But my friend took me to the Marine recruiters the other day to try and convert me (to the Marines). The got me interested in counter intel because it sounded crazy, CI is not an entry level MOS so they told me about MARSOC which isn't an entry level MOS either, They told me I could be in MARSOC in the intel community initially, then I asked about MSOAG. They said I could get there initially too.
Again, I was always joining the Army because I have zero motivation to become a Marine. I'm not planning on doing advisory missions for a career, I was just asking about it.