I don't have the 8.1 update yet and I live in the UK and own a Nokia 920 Lumia. I have checked to see updates every day and have it set to update automatically. When is the 8.1 update?
Check with your carrier. You could also use Nokia (now rebranded as Lumia) Software Recovery Tool. It would wipe all your data, but you can restore backup during set up. Just run backup before using the tool which will only flash the latest approved version for your device.