Well Linda, your broccoli is going to
seed. I don't know if you have had any sizable heads yet but if they are still small, it can often be attributed to hot weather. Your best bet is to cut the heads off and the
flowers before they get pollinated. You will then have a chance of getting side shoots and could still end up with a good size head of broccoli. But don't neccesarily wait to get something of huge size that you see in the stores. Home-grown ones don't usually look like that.
Good Luck!
Pamela