Birds in the wild don't have a social heirachy, they're one big equal flock. So a higher bird won't be a dominant bird.

But it can be hard to manage them when they're somewhere like your head simply because you can't see them and they feel safe and happy up high and won't want to come down, and after a while you start to realise that you really don't want your hair messed up and pooped in all the time. I suggest you discourage her from using your head as a perch sooner rather than later. It's tricky to un-learn a habit, but it's easy to teach them good habits right from the start.