Week 1 - Predominantly Beach Parties, so there is more opportunity for underage schoolies (17) who wont be 18 to enjoy.
Week 2- Very little beach parties maybe 1 or 2 throughout the whole week, mainly a week for the 18 year olds to go clubbing.
From what i have been told even if you are 18, Week 1 is still the best week to go up, more people will most likely be there aswell as for 2nd week, NSW people look to go to places like terrigal because they are more chilled.
I'll be up there in week 1.