There are six stages of change model: pre-contemplation, contemplation, preparation, action, maintenance, and termination. In the pre-contemplation stage, people are in denial mode and do not think about changing the unhealthy lifestyle.
In the contemplation stage, people think that their unhealthy lifestyle is harming them and they think about it. In the preparation phase, people decide to improve fitness and ready to come in action within a month. Therefore if I have made a plan and ready to implement it in next month starting then I am in the preparation stage of the change model.