Well especially there in OK where I assume you have a long time left til frost, after you till your Bermuda grass, a whole bunch of weeds including more grass are going to come up unless you do something. Couple of choices would be to till it again just before frost, which would get rid of the weeds that came up and then let the frost kill the next set. Or cover the soil. You could use clear plastic, to solarize it... heat up the soil enough to kill remaining weed seeds. Or you could cover it with something like a thick layer of newspaper, that will smother the seeds, but eventually break down. That's called sheet mulching. Type that into the search box in upper left of most pages and find a lot of info about it.