It is apparent that you and your child's father agreed on a parenting plan. This implies that you and he either wrote or agreed on the language that "it" contains.
I am assuming that "it" is either an order or judgment that the court has entered, or a memorandum of an informal agreement between the two of you. Either way, the language relating to school means only what you meant it to mean when the two of you agreed to it. If you didn't answer this question back then, there's no way to answer the question now just by looking at the document.
You will need a new judgment or order, or a new agreement resolving this issue.
Look the the express language of the agreement/judgment and determine if it defines when school starts. Assuming it doesn't, you may have a good argument that the child is now in school though the other parent may say it is daycare.
Consider mediation. The court is Scappoose may have a program whereby you and the other parent can mediate this issue.
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