The ticket booths generally open an hour before the park does. So if you want to get in as early as possible, be there before the park opens to get your tickets, and you can enter when the park opens.If you are worried about not being able to PURCHASE tickets, don t worry. It won t sell-out tomorrow. It usually only fills to capacity on Christmas and July 4.
I have been to disney many many times in my life. We have gone without buying tickets until we get to the first theme park at disney before. I would get to the magic kingdom a bit early because it is one of the busyest park, so there are a lot of people buying and picking up their tickets there. You don t have to be there before the park opens or right after it opens, but you are going to want to get your tickets with in the first hour and a half of the park opening. This is also the best time to go because the people with really young kids don t arrive to the park until about 10:30am- 11:00am.