The servers are trying to roll out to several hundred million users. Your turn will come.
If you really can't wait, you can force the upgrade by getting the Media Creation Tool & running the install manually from a USB stick.
Don't try to install by booting from the USB stick, as this would invalidate your free upgrade & you'd need a true Windows 10 key to install.
Without that key, it will reject the install & tell you to run it from inside your current working OS instead - by booting as normal, then running the setup.exe on the stick.
That way, when you get to the install key window, you can skip it & it will authenticate based on your existing install.
The USB stick isn't compulsory - if you have only a single machine to update, you can just run the tool straight from that computer. The USB stick saves multiple machines needing multiple 4GB downloads.
The options are something like [not verbatim]
'Upgrade this machine' & 'Upgrade another machine'
'This' will download & upgrade just that machine, 'another' will allow you to construct a bootable installer on USB, which can be run at boot, or from a running system.