The Wonderful Garden by Edith Nesbit

I don't know exactly how it happened. Perhaps Caroline was too sleepy to bump her head seven times on the pillow before she went to sleep. Or perhaps that excellent spell cannot always be relied upon to work. At any rate, none of the children woke till Jane came to draw up the blinds and let the half-past seven sunshine into their rooms.

Then Caroline woke quite thoroughly, looked at her little watch, and leaped out of bed.