It's possible that you might be trying to change the wrong status indicators. Make sure that you are editing your own profile and not your mother's. On the right side of the page under the column titled "Edit Family," find the status indicator that says "mother is confident" and click the circle next to it. (You can also select the one that says "mother is confirmed with DNA" if you meet the requirements on this page and include a DNA confirmation statement in the sources section on your profile.) Then, save your edit.