I went through the test, taking it with my childhood experience in mind and scored as INJ.
I read through the descriptions and I exhibited a combination of INJ, ISJ, and ITP traits. Actually I identified with ITP somewhat less than the I..J types because as a child I remember being very stubborn, inflexible, and resistant to change. As a child I was pretty high strung and had strong opinions on things and the way things *should* be.
The general consensus on this forum seems to be INTP for my type, but if I compared my childhood to the childhoods of other INTPs, there's quite a difference. Compared to them, I was more inflexible and high strung. I needed requirements spelled out on assignments more. I wasn't quite as reclusive, I was somewhat more sociable and relied on praise and external validation more.
So the question is, did it just take me longer to 'develop' into an INTP type or am not an INTP but perhaps an INTJ or even some other I..J type?
I got INJ too, FWIW. I think typing someone this way (based on a third party observing behaviour) can be tough, because different motivations can underlie the same behaviour or reactions. Not that traditional tests aren't error-prone as well.
I don't think being high-strung is unusual in INTP kids. I would think it's pretty common in introverted kids, even Ts. Questions about 'new experiences' and 'need for approval' are kinda difficult for me to answer. It wasn't that I wanted tons of approval (pretty much all kids need some) and an unwavering routine. It was more that I was a very anxious kid, and I feared criticism and embarassment and the unknown. I acted agreeable in school, etc. because I didn't want too much attention on me. So my behaviour might have been similar to a child who wanted to please authority figures, or avoid hurting peoples' feelings, but the motivation behind it was different.
I don't believe type is fixed from birth either. Or that type development follows a set routine ('the ego chooses the dominant function first...'). It doesn't seem that's the way it was for me.