Yes, you are correct in washing them now they will stay for longer because it's not as distressed. You should put it in the dryer as well because that locks the dye in place. Although many people recommend you to not put it in the dryer, if you sized properly they will be fine. If you wash them now they won't be noticeably lighter, it will be coming from dark dark blue to dark blue.
Okay thanks, so if I put them in the dryer they will shrink a little more? This is what I would ideally like to happen.