I first got interested in MBTI stuff when I was around 17, at which time I typed out as an INFP. I continued to test as INFP all through college (though T started appearing near the end), until somewhat recently, and now I'm ISTP. When I first started learning about MBTI I had dismissed the ISTP type for me because of its standard association with things like motorcycles, cars, and skydiving (I have zero interest in any of those things), but the sporty and technical nature of the ISTP does resonate with me quite well.
Reading through the descriptions of both types, I'm starting to wonder if maybe I was always ISTP but the circumstances during that part of my life made me type out differently. I was under a lot of emotional distress during that time, and only after I worked out the emotional issues did I start to test out as ISTP. Is it possible that ISTPs under a lot of emotional stress (unrequited love, emotional manipulation from close friends, heavy pressure to express emotional sentiments in group settings, etc.) might type out as something different?
I'm an ISTP female BTW, in case it makes a difference