We all know that a good nights sleep is important, year round, and especially for school (or work!). But during the summer our sleeping hours tend to make a big shift from the school year. And getting our sleep schedule back can be one of the hardest things about going back to school. It's most certainly not easy to go from going to bed at 4 in the morning, or even later then that (I know that it can be very easy to pull an all nighter in the summer, LOL!), to going to bed at your usual bedtime. Nor is it easy to go from waking up around noon, to waking up at your usual wake-up time for school. With a few weeks of summer left, about 2 and a half for me at the time of writing this (some people may have a few extra weeks, or even less), it's time to start adjusting back into school mode.
I tend to have a really hard time sleeping on the night before the first day, and it's worsened by a messed up sleep schedule. Remember that excitement and anxiety over the first day of school can keep you from falling asleep. Though I don't have trouble waking up on the first day, and my excitement keeps me going and feeling energized throughout the day, I tend to pay for the lack of sleep the second or third day, up until the week is over. And of course while the tiredness later in the week usually gets my to sleep much quicker, I shouldn't use this kick in the behind to adjust my sleep schedule. There's really no reason that anyone should have to feel tired and groggy during the first week of school, or even the first day.
While you still have some flexibility with your time, it wouldn't be a bad idea to start at least trying to go to bed earlier and waking up earlier. Try to start going to bed 30 minutes to an hour earlier every night, or every couple nights. This will help your body slowly get used to the change. You don't have to get all the way down to your bedtime (but or course it would never hurt to do so), but try to get within an hour of it. Pick a time (ex. 4:00 am) and gradually get earlier from there (2 o 3 nights earlier: 3:30, a couples nights later: 3:00, and so on...) Try to get off the computer at least half an hour before this time, and get try to do something relaxing, not involving technology. Read a book, take a warm shower, listen to music that relaxes you (avoid pump-up songs, and dance songs if they really get you going), or anything that relaxes you. Just try to keep off the internet and avoid texting. It's very easy to get ignore your bedtime when you're doing these things.