To really be good for burning firewood needs a minimum of 1 year to cure and dry out before burning it.
But 2 years of cure time for firewood is even better. So while you're burning your current supply you should be cutting down and preparing firewood throughout the winter for the next few winters.
Try to keep at least a year ahead on firewood and continue to cut and prepare firewood throughout the summer.
Cutting and preparing firewood in the winter will keep you busy and make winter fly by.