ISTJ's have an "internal guidebook" of sorts that is composed of things that they've decided to focus on throughout their life. A lot of SJ's focus on happy childhood memories, so that is why they talk about the good ole' days, and they don't want things to change so much. If you've focused on things different from the norm then your "internal guidebook" could be pretty different from most SJ's.
Overall most of the descriptions for sensors aren't always accurate particularly if the person is fairly intelligent. For example an intelligent ISTP is more likely to be an engineer than a mechanic, even though most ISTP descriptions make them seem more like a mechanic. Most likely you are a bright ISTJ, and that is why you don't relate to the standard ISTJ descriptions. If you are more interested in proven facts rather than possibilities, and if you have a keen sense toward details that you focus on, then you are probably an ISTJ (or maybe an ESTJ, but I'll assume you've figured out the E/I dimension).
Kinda sad the way an
intelligent sensor gets to occupy the neither region between S and N. But this has been discussed, digested, and defecated so I won't go into that.
I think it's good when people question whether they're S or N because that forces you to understand the functions better and usually the difference between sensing and intuiting is the hardest to tell. Once I got a good understanding of what Se, Si, Ne, and Ni was everything got mashed together and I had to look a little harder in order to find a meaningful difference. If it helps, most SJs I know don't fit the typical SJ profile very well either.
If you're an NT you'd prefer this:
Attention to concepts, meanings, interrelationships, and probable or possible futures with a focus on the principles and criteria involved. An abstract, problem-solving approach.
If you're an ST you'd prefer this:
Attention to the tangible realities based on current and past experiences with a focus on “objective” facts, criteria, or principles. A just-the-facts approach.
Source
ISTJ Profile
If you ignore all the duty-bound parts, do you think it fits?
INTJ Profile
Are the autonomy seeking parts of the INTJ description what you identify with
most?
Also you're more than likely to have come into contact with more ISTJs than INTJs. Some times it helps to identify other people that you think might share your type and figure out how similar/dissimilar you are to them.
I'm not going to say what type you are because honestly I don't know. And if you're on the border between S and N I think that's a pretty good place to be because you can do both.