Replying to Are 169's too small?

Alright so I just bought  the volkl walls and the shop didnt have 177's which i planned on getting and only had 169's. the guy i talked to who seemed to know his stuff convinced me that 177 was too big anyways and that I didnt need any bigger..i am 5'11 and 165lb. is size a big deal and what is the advantages/disadvantages of having a bigger ski? I am aware that there are a billion other threads on ski size, but i dont have the time to read through a ton of threads.