Hi @paxtonhub:
The parent pages (called master pages in previous versions of InDesign) are in charge of the body pages—this is where we define the margins, columns and add repeating information like headers, footers and page numbers. As per @Willi Adelberger's answer, you should be defining the margins on the A-Parent, which will roll through the body pages.
As a heads up, if you have been defining the margins on the body pages, you have introduced overrides on each of them. You will want to remove those overrides by selecting the body pages and reapplying the A-Parent to all of them before moving on.
You can learn more about parent pages here: https://helpx.adobe.com/indesign/using/master-pages.html
~Barb