I always believed that your type stayed the same throughout your whole life. Coming from a very large family (8 siblings) seeing that we have all been raised the same and we have all been homeschooled so we have also had the same school experience, but we are all extremely different in our personalities and have kept the same personality throughout our whole lives always made me believe that we were born with our types. Ever since I've joined this community though I've found a lot of people talking about how they used to be something else and now they aren't. I don't know if I'm missing something and I'm hoping someone can explain it to me. I was also thinking that maybe some people were mistyped in the first place or that they were suppressing part of their identity. For example my sister is 100% an extrovert, she has always been, but after going through an unhealthy friendship she became very shy and lost all of her confidence which in turn made her socialize a lot less. I don't think that she became an introvert during this period of time, but that she was not in her best state.

Can you guys help me understand this? I would especially love to hear from people that have 'changed' there mbti type.