Hmm, I think if you have a good vibe you should go with it and MBT be damned! Because I think according to MBT - ISTJ/INTP is an odd pairing. Also, I think the fact she accepts your quirkiness is a good thing.
I have a good ISTJ friend and her relationship with INTPs is touch and go. There is a lot of difference within the INTP range though, especially in regards to general sociability and extraversion and also moodiness (yes, INTPs can be hella moody, I know enough irl that if anyone tells me different I will laugh and say HA! in your face).
I think for my ISTJ friend, when people (regardless of type) are too in their heads and not communicating, it REALLY throws a wrench in things. Because, imho, ISTJs are not naturally gifted at understanding what people are feeling/what is motivating them *and* empathizing.
She totally does not get nor really wants to delve to deeoly into 1 INTP we know, with another she had a huge falling out largely precipated by lack of communication and the INTP seemingly becoming hostile without explanation, and a third, she is on good terms with (after a rough patch)
In this case, seriously, screw MBT. I would only refer to it once you hit upon problems, until then, you can have an optimistic and clear head.