If you do make it in before June 18th, be content with the sights, sounds, mechandise and food. Ollivander's popularity was way underestimated and the Hogsmeade actual shops are quite small. Only a lucky few will get the full experience in the months ahead.
If IOA were a ship, it would capsize from the imbalanced crowds we will see.
If I could afford it, I'd definitely get an annual pass now. (along with a bus pass to save on parking)