Is it normal to have such irregular cycle?

I’m a little concerned about my period since I’ve never had consistent cycle lengths. I hear some girls say that they can predict their period very accurately and that they get worried when their period is a day or two late. Since mine are so irregular (it’s been this way ever since I started having them), I don’t even have a concept of “late periods.” Is my cycle normal enough? If not, what should I do about it?