Nah, i don't think all women know when they are ovulating. Otherwise, there wouldn't be SO MANY pages with ovulation predictors and posts about that stuff!
the only way I can tell is I feel like I'm swollen down there. I am actually ovulating today, and 2 days ago I consulted an ovulation predictor to see when that time would be. Now that I know when it is, I notice it. So do what I did, and soon you'll notice how your body changes and see it for yourself!