No, not too soon if you want to be organised.
You could make a list of what to buy who then track online discounts (hardy potter lego, etc).
Or make a list and buy it all in one/two days.
There is a thread somewhere on MN wuth a list of things needed for the Christmas period that you don't want to run out of. It has such gems as:
Extra batteries for all new toys
Extra bog rolls
Candles
Aluminium foil for leftovers
Drugs (paracetamol, rennies, burn cream - for hot-oven-incidents).
Etc.
Listing and ticking things off that list helps us be organised (whether that's housework, the swimming bag, picnics, back-to-school palaver). Be sure to include/delegate a lot of the list to partners/older children. Bearing the brunt of doing EVERYTHING at Christmas (or picnics or what have you) sucks my will to live.
DS is a December child. We have already bought a gift for each (v cool microscope and a rugby ball) and a couple of bits for his stocking, including a grow your own crystal set.
I haven't even thought about Christmas food yet. I'll design my cards next month (handmake about 10 for family and abroad-friends).