Good luck with your garden! Very few activities are as rewarding, in my opinion, as raising a garden. It's true that we have to compete with some wildlife and pests, but that's always been part of the game.
I always plant more than we can handle -- the deer and rabbits sneak some and we still have enough. The bugs will sneak up on us and it seems like they just came out of nowhere overnight. That's part of the challenge.
Your garden is roughly the size of a 2-car garage -- you can get plenty planted in an area that size.
I would say that the only thing you can do wrong with a tiller is to work the soil when it's too wet. That can create cakes of mud that ruin the texture of the soil for years. If you're tiller is making mud slices, stop and wait till it dries out some. If you can grab a fist full of soil and squeeze it into a ball, it's too wet. If you're not sure, it's too wet. You'll know when it looks right. As long as it's dry, you can use a tiller to weed or cultivate as much as you want.
All things considered, I could probably buy produce at the grocery cheaper than what I spend on my garden, but you just can't beat the taste of fresh corn, tomatoes, cucumbers, peppers, asparagus, etc. Add to that the satisfaction of watching your crops grow.
I think this country would be in a much better place if everyone had a chance to raise a garden. . .