Many people claim their type has changed over the course of their life. I am of the belief that some attributes of your personality are unlikely to ever change deep-down, they will always be our 'default', but when you read further into how the functions work and develop, it makes some sense in favour of that argument.
So for example, I am a textbook INFJ however I see many similar traits in the types next to mine like INTJ and INFP. However, when I see people online saying "I'm an INFP but I'm also an ESTJ!" I'm like, no...they're way too different for you to be both. Interestingly enough, I have seen that the people who study this test say it is very possible we can all test for the wrong type because we're doing a simplified version online and the real test is very long, in person and administered by a professional.