if you've got a spare battery you can try, I'd do that. Your battery might still read an okay voltage, but a few cells might be bad / dry / shorted and it's lost it's cranking capacity.
Also, make sure you put the battery all the way, installed in the car (assuming you've got a spare), don't just use jumper cables to connect it.
Also, make sure you put the battery all the way, installed in the car (assuming you've got a spare), don't just use jumper cables to connect it.