I'm on one of the beta version of High Sierra, I turned that off in the settings but now I can't download the official release High Sierra? App store downloads to the end and then... nothing. Then it just comes back with download again?
You could search high sierra in the Appstore if your mac is from 2010 or later, but I don't recommend updating yet, as the file system changed and most programs haven't adapted to it yet. Most games will run much slower than they did before until they update to 10.13.