You can add editors to your site.
While in edit mode click the 'Share with others' icon.
Warning: There is no revision history in New Sites so if an editor makes unwanted changes you can't easily restore the page.
In the link sharing window make sure to select "Off - specific people". If you select :On - public on the web" ANYONE will be able to edit your site. See the image at the bottom-left of this page.