Hi, Brandie!
We like to balance our early-open days with sleep-in days on each trip to Walt Disney World, so that we get to take advantage of early-morning perks AND feel that we've relaxed a bit while on vacation.
If you are staying at a Walt Disney World Resort, then look at the morning
Extra Magic Hours which are offered during your stay. I suggest heading to Disney's Animal Kingdom during an EMH if you will be visiting during the warmer months, as the cooler mornings will allow you see the animals at Kilimanjaro Safaris when they are at their most active (before the heat drives them to seek shade and a nap...) With the opening of the New Fantasyland expansion, you'll want to enter that park as early as possible, too.
At all of the parks, many Guests arrive later in the morning, so if you've already experienced many of the attractions by that point, you can relax your pace a bit, or even head back to your resort for a little mid-day pool time, too. Depending on your schedule, try to plan an early day followed by a sleeping-in day. It will be much easier to get up early one morning if you were all able to sleep in the previous night. Also try to avoid an early morning the day after a late night, if you can do so.
Send another question with your dates, Brandie, and I'll help you carve out a plan! It will be fun!