Apparently I'm running a marathon!

Hi all! So I just found out today (!!) that I got into the NYC marathon after applying about a month or so ago to run for a charity. Needless to say I'm freaking out but I think I want to bite the bullet and do it!! I've never done the full 26.2, but I have done 6 half marathons, the most recent being at the end of April. And I ran a 10 mile race last weekend so I'm not totally starting from scratch here but any tips? Is it too late to join the marathon training group? I am so nervous but it excited to conquer 26.2 for the first time!