autopercibirse

A technical, fairly recent term from psychology and identity discourse describing how a person perceives or identifies themselves, distinct from how others perceive them — common in academic and legal writing about gender identity.

• La ley reconoce el derecho a autopercibirse según la identidad de género. — The law recognizes the right to self-identify according to gender identity.
• Muchos jóvenes se autoperciben de forma distinta a como los ven sus padres. — Many young people perceive themselves differently than their parents see them.
• El estudio analiza cómo se autoperciben los adolescentes en redes sociales. — The study analyzes how teenagers perceive themselves on social media.

A formal, technical register word — in casual conversation, verse a sí mismo or considerarse are what a native speaker would actually say.