“I’m just not a morning person” might have expired three years ago. Check the date on your self-descriptions.

Descriptions of yourself get written once and then quietly stop being updated. The statement was probably accurate when you made it, which is what makes it so easy to keep repeating, and in the meantime your circumstances, your sleep and your interests have all moved. The sentence stays fixed while the person it describes does not.

Pick one thing you routinely say about yourself and test whether it is still true. Run it as a small experiment rather than settling it by argument. Two weeks of evidence beats a description you have been carrying since you were seventeen.