As long as your current build is legal and activated you can use the update assistant to obtain the latest update (Creators or 1703).
Download Windows 10 You can also create an iso with which you can burn to either disk or usb and perform a clean install (probably the most desirable method of install)
Remember if you clean install that when your asked for the activation key, click 'I don't have one' as yours is stored online and windows will activate as soon as you go online.
The reason why you actually did not update could down to a number of reasons and if it happens again try the update troubleshooter:
https://support.microsoft.com/en-gb/help/4027322/windows-windows-update-troubleshooter