If you dream that you are cutting your hair yourself then that shows that you are ready to take affirmative action for change in your life.
This can be something as basic as a new look for yourself, hairstyle, wardrobe, character, etc or it could be something much deeper such as a need for a whole new perspective on life.
Cutting your hair or getting your hair cut shows a need for freedom from something that holds you back which can be something within your point of view, your emotions, or lack of actions on your own part or someone in your life who is holding you back.
If you dream your hair is being cut by someone else it is likely you are only now formulating what it is you need to do, what actions need to be taken, and you are still in the process of coming to terms with the change that needs to be made.
However, if you are cutting your own hair this shows that you are ready to take action or are already taking that action. Likewise, the more hair that is being cut off the more change you are ready to make!