Photos app to Google Drive share

I'd like to send photos from the Photos app to a folder in my Google Drive, but when I select the photos, choose the "share/send" icon, then choose Google Drive, the Google account I need isn't an option to choose from.

The needed account is logged in within the Google Drive app.

How do I get that account added to the list of accounts within the "share/send" function? I do not want to upload from within the Google Drive app because it's clunky to select all of the photos, and then I'd have to reselect them all within the Photos app to delete them from the Camera Roll after they've been uploaded.

One other thing to note -- the Google account I'm trying to use is a child account. Is that what is stopping me? Separate issue that may be related is that I can't get this child Gmail account to work within the Mail app on the iPad, either.

Thanks in advance for any advice. New Christmas gifts can be so frustrating at times! :)