Definitely not too early - I had a jar last year that I found at the back of the cupboard from 2012 which was delish!!!!! The falvours had really matured and changed into something deeper and oh so moreish!!
It needs a good few weeks to mature in general anyway, so now is a great time to lay it down (i.e. mix it up and then ignore it).
Other things that you could do are putting together "cake mixes" or "cookie mixes" - weigh out the various dry ingredients into small freezer bags (so flour, baking powder and cocoa together, chocolate chips in another bag, sugar in another, for example), combine those in a larger bag - all ready to mix, and add a note saying how much butter, eggs or other wet or perishable ingredients you need to complete the recipe. That can save valuable time later when you want to whip up a seasonal treat in a hurry, the DCs need something for school at the last minute, or you get a phonecall saying "Great Auntie Julia and I are 20 minutes away and decided we'd call for a cup of tea"!
Another option is to make up things like sausage rolls or do other baking and freeze them now for later. Or make your bread stuffing (or even just make the breadcrumbs), or other bits.
I like to have a few regular family meals (in family sized portions, and single portions to allow either nights when it's just 1 person home, or when "GAJ and I" are just calling unexpectedly right before dinner!! and you need to stretch it) frozen as well for the festive season - now you have time to make what you love as a family, and spend the time on getting it made, adding in all the veggies etc, letting things that need long simmering to cook, etc - but you will then have them for days when it is wet and miserable and you have 5 different shops to visit, there's a nativity on at school that you MUST see and there is a big presentation at work tomorrow so you need to think it through AND wash your hair all on the one mad evening when the DCs are tired, cranky and hungry.....