Will my iPad just turned off after I put it in charge and now I can't turn it back on no matter how long I press the on/off button.
Try the rest of the steps in this support article and if you still can't get the device to power up, make an appointment at an Apple Store and ask them to take a look at it for you.
If your iPhone, iPad, or iPod touch won't turn on - Apple Support
You can not overcharge the battery. I have an iPad 3 that has been plugged into power for about two weeks and it wakes right up when I tap the home button or the power button.
I would try the forced restart again or try Diana's suggestion again. When you do the forced restart, do you see the Apple logo appearing on the screen?
To force restart your device, press and hold both the Sleep/Wake and Home buttons for at least ten seconds, until you see the Apple logo. After you see the logo, let go of the buttons.
Hi. I don't believe you can overcharge an iPad. The internal charging circuit cuts off when the batteries are charged. Just holding the Sleep button for about 20 seconds should wake it up.
iPads can not be overcharged regardless of how long you plug the charger in for.
What should I do if I have overcharged my iPad and it won't turn on?