Generally, hanging your entire identity on it as a way to be special and/or unique and/or rare is a good indicator that you are not an NJ.
Real NJs understand the problems and struggles that come from weak Se, which includes but is not limited to poor sensory awareness, bad special awareness, getting injured because of miscalculating the sensory environment, having an identity crisis when faced with something that challenges their understanding of the world, being not able to easily switch tactics and/or give up on the vision they have for an event / a story / whatever and thus giving up on it completely because they can’t have it exactly the way they want, being unrealistic in their self-expectations, leaping to conclusions without sufficient proof, and not learning things accurately or well due to filling in the blanks rather than extensive study.
If you do not visualize things completely in your head, and do all your arranging and editing ‘up there’ (as opposed to while you are doing something) then it’s not likely you are a strong Ni. NJs have told me their writing process, for example, is planning out a story completely before writing a single word and then simply typing it out, especially if they have time to do it (this goes also for assignments, e-mails, etc). You may notice mbti-notes is quiet for a week at a time when answering asks, then pounds out hundreds of words and a dozen answers within a couple of hours on her “answer Fridays.” This is because she was formulating what she intended to say in her head beforehand, then could just sit down and write it out in a few minutes and hit ‘post.’
Lastly, if others do not have trouble following your thought process. Ni’s ‘come up with things’ where outsiders are not sure how they reached that conclusion, based on the provided skant evidence. Futuristic predictions, assumptions about people’s motives or their true intentions, but always focusing on some future event with a sense of certainty, because Ni drew the conclusions, foresaw a likely ending, and passed it on to the judging functions for judgment. These are often incredibly specific predictions, so if yours tend to be more generalizing and/or changeable with additional info, you’re probably using Ne.
If you make it up well as you go along, probably not high Ni either. P types innovate and improvise skillfully on the fly, NJs do not.