I've always heard that spiced holiday ales generally take a little longer to condition and for the flavors of cloves/ginger/nutmeg/cinnamon to mellow out. Not sure on your exact recipe, but 3 weeks until Thanksgiving may not be long enough to really cut out the ginger bite or some of the other flavors?
Wouldn't hurt to try it in 3-4 weeks at Thanksgiving; its quite possible it will be very drinkable by then as well. Should be pretty good at Christmas and New Years though!
I started mine a little late and it won't be bottled for another 2 weeks. I'll be drinking the earliest one at Christmas and I'm a little worried that even that won't be long enough? Someone with more experience is sure to chime in.