Myers and Briggs would argue that your personality doesn't change, but you do learn new things about your personality. That said, it would be interesting to see how this works on older adults.
Personally I'd say I was introverted due to fear of being ostricized in public till I was about 13 or 14. According to MBTI, then I'd be 'INTP', now 'ENTP'. My personality was probably always 'ENTP', I just overcame the fear.
AFAICT, MBTI wouldn't really pick up on that.