Most of the U.S. is an "At Will" employer.
You may leave at anytime, with or without Cause.
You may be terminated also, with or without Cause*.
Best to just call or in person tell the boss you are quitting.
As a child, you cannot sign a binding contract.
You will be fine quitting at any time for any reason (or no reason).
If you apply to another job be sure to list this job.
"No Call, No Show" is called Abandonment of Employment, it is not viewed well by future employers, as it shows lack of responsibility.
*Terminated for Cause. When an Employer has found fault with the employee. The employee is fired for "cause", being so terminated the employee generally cannot collect the Unemployment Insurance the Employer has paid, unless a hearing is held that finds the employer wrong.