The purpose of rolling is not to perfect the soil. The purpose is to ensure the seeds are in good contact with the soil. Then the soil will help the outer coating of the seed remain moist throughout the day.

Assuming you are in the Northern Hemisphere, you are seeding at the very worst time of year. I wish you good luck, but if you are seeding with a cool season type grass (fescue, rye, or Kentucky bluegrass) then it is going to have a hard time surviving the summer heat. If you seeded bermuda in the south, then it is too early...unless you live in Phoenix.

Again assuming northern grass in the north, then don't get discouraged if you have a lot of weeds in July. Continue mowing the weeds through the summer and in August you can get going during the BEST time of year for seeding. By seeding in late summer after the heat breaks, you will have a chance to seed again if you see thin spots. Then the roots will have all fall, winter, and spring to grow and harden off for next summer's heat.