i'm still of the opinion that down to your knees looks dumb, and you can layer down some from a large, but i don't quite share most of ns's taste, and i've gpt heartburn, so op can follow either bit of advice.
i'm 6' or 6'1" and a little on the bigger side and i just got that jacket in an XL, it's perfect for me. baggy but definitely not down to my knees at all. i don't think i would have been as happy in a large.
get a large dude. buying super tall jackets is going out of style. once you grow up a bit and get more mature you wont want it anymore. if you get a large you can keep rocking it for much longer.
If you don't want to look like a fool while wearing it off the mountain, get a large. Even a large is considered "way too big" by some people. I have the On Deck and have gotten that remark multiple times. I just say back "its supposed to be this big" and walk away. And I don't think a large is "too small" when it comes to steeziness on the mountain.