People's concept of self evolves over time and with experiences. The self is a collection of past behaviours that inform present and future behaviour.
Yet, the self doesn't exist on its own. The self reflects the context, and the context shapes the self.
The self influences our psychological realities. For example, you don't put in the effort to clean up, dress well or take care of yourself because you believe you're unattractive.
Also, the self is constantly attuned to the social environment and makes adjustments to obtain the desired outcomes. Likewise, others ignore or avoid you, and your belief becomes reinforced.
The self changes as it develops awareness and agency. Self-awareness is a conscious knowing and understanding of your own character, feelings, motives, and desires. Agency is the sense of personal choice and the ability to exercise personal powers. When you have agency, you can take action independent of social pressures or divine interventions.
Don't use your past as an excuse. Increase self-awareness to observe the consequences of your actions. Use your personal agency to become a better person each day.
You, as much as everyone else, have the right to change.