Welcome to the forum jeremyd.
Do you want to race or just go out there and finnish? If you want to do it for the fun of it and you are only getting into cycling then don't worry to much about all the technical stuf; get on your bike and put some km's on.
I don't think it is to late to start training. I did the Argus this year after only about 300km on the bike for the year (had a big wipe-out that prevented me from training), but I ride to stay fit and to enjoy it, not to race with the big oaks.
Set your goals and start training accordingly, try to do a 2-3 hr ride once a week to get the time in the saddle and you should be able to finnish the race, just don't expect to much if you don't train hard.