Yes you are doing it right since your grandfather used the soil for gardening it has very good soil and since it has not need used for years it will be in great shape. You did right by adding your compost.
Now the problem will be the grasshoppers they will eat you alive. Hard to stop them with the organic pest control, please post back if they work and how you made it of were you purchase it. I would be interested.
100 x 100 is almost my property size with the house on it. City land is smaller and cost a lot. My land is 100 x 125.
So you will be growing a lot of food if you can keep the grasshoppers from eating it all up. The rest are easier to keep off your plants with the electric fence. Birds will be your number two problem. See if there is some type of low sound device that will keep birds away.
The large growers use a black mesh screen that goes over there garden, it also helps with the heat too. This black screen is not cheap but lasts for many years.