Raw denim, meaning unwashed or unfaded, needs about six months of consistent wearing to break down and mold to your body. This process takes time. Washing them before your ideal shape is achieved counteracts this effort.
To keep your jeans clean during this time you can spot clean stains with a mixture of vodka and water (50/50 solution) to kill bacteria and odor, and air dry. This also helps your jeans last longer, as excessive washing will breakdown the fibers in the fabric quicker.