school year's resolution
A commitment an individual makes to a positive lifestyle change to coincide with the first day of school -- when daily schedules for both kids and parents tend to become more regular.
Example:
There's no way Sarah could avoid lying around and stuffing her face with fatty food during the summer, but she's making a school year's resolution to eat better and exercise.
There's no way Sarah could avoid lying around and stuffing her face with fatty food during the summer, but she's making a school year's resolution to eat better and exercise.