An 8" circle I believe is a good indicator.
Most days, I can hold my own and shoot beside anyone and be confident in my accuracy. An 8" circle is no problem out to twenty yards.
However, that 8" circle becomes much smaller, after a two hour sit on Saturday morning, after working fifty hours, and staying up a bit too late to watch a movie with my wife on Friday night. Suddenly twenty yards is a long ways.
If you have refrained from hunting with your longbow for two years, it means you care. If you feel you are ready, then I for one am sure you are.
As hunting season approaches, putting yourself in a realistic hunting situation, and making one good shot without warm up is going to be the real test of your accuracy.
When the time comes, you throw the thought of the 8" circle out the window, concentrate on a single hair, and your hands, your eyes, and your longbow will do the rest.