1st season..winter fronts... 12m kite? Sounds like trouble.

Seriously mate winter kiting is for the more experienced and even then can be a bit of a drama. Big swell, going from underpowered teabagging to white knuckle fever overpowered in seconds - then back again.

Then there are the fronts.. I think everyone has mentioned fronts already but they are super important to keep an eye on. See one coming - then get to shore and land your kite immediately. Not "one more run" - do it immediately.
TBH tollair - you are asking a more than a bit much of your experience and skill levels to be taking on winter at this stage. Best bet would be to get a full summer season under your belt next summer. Use the time to save up for a 8m-ish kite (if you are planning on keeping your 12m) and then think about taking on your 1st winter next year.
Check yaself before ya wreck yaself - as Grandmaster Flash would say.