Hi,
1)Prob not...is it finished already?
2) Of course you can get into shape. I would start by getting a used road bike. Alternate days between the two bikes with at least one day a week off the bike. You will want a periodised training schedule to avoid overtraining. A good coach would come in very handy; if you can find one.
By coach, I mean someone who will work with you. If you do use an outfit like CTS, if they offer a program where you go out there and your coach gets to actually see you once...that would be a lot better. Nutrition will be crucial. Ideally you should drop a pound a week between now and the start. Don't go over a pound a week.
Learn about ultralite camping gear, and do some week long trips to discover what will work for you. Make a couple of them backpacking trips and you'll toughen up those legs. Lexan knives and spoons work. While down is lighter, it loses it's warmth when wet. There is a new bag that backpacker liked that mixes down with a new synthetic. Very slick, and worth looking into. What you want in a stove is reliability. Find out what AT hikers like these days. Actually, hit a couple backpacker stores when it's not busy, and talk a while with a salesperson who is a hiker. You will also need to find whar works for you for food. This is tricky, since you will be burning more calories than you can carry. I would include a bottle of grapeseed oil in my mail drops. You can carry any oil you like, grapeseed is one of the better choices. I used to carry two 'luxury' items. They used to make small aluminum drip coffeemakers. I got mine in a yard sale. Ask your Mom, she may know someone who has one. They fit a Melitta cone perfectly, and weigh next to nothing. I would bring those one pot foil packets of gourmet coffee; and have fresh brewed coffee every morning. Canned milk will last 2 or 3 days if it's not hot. I also used to carry a little canned milk. Obviously, it doesn't last long, but it's real nice while you have it. It also livens up some of those dried backpacker meals. The Army spent about a million developing the Bakepacker.
http://www.bakepacker.com/
This is so cool. While the device itself is wonderfully light; using means carrying
boxes of cranberry bread mix, eggs, and stuff for pizza
If you haven't spent time in the backcountry, you have no idea how good pizza can taste. Last Mtn bike I bought was the last gary Fisher SuperCalibre to come without shocks. That was, I don't know, 10 years ago? Can't help there.