You have time. Most marathon training plans are 16 or 18 weeks so from now until new year concentrate on getting a good base in. Don't know what you're longest run is but even if only 6,7 adding a mile a week should get you a decent head start. Main thing is get a good plan, look at mcmillan pace calculator to get an idea of training paces. Don't get too fixated on the time for your first one, the first one is a huge learning experience.