In a similar boat as you
@Offline I initially typed as an INFJ when I first took the mbti test (was 15 then) once coming out as an INTP/ISTP and eventually settling with the latter. Something always felt wrong about the description though, I just couldn't 100% relate to their mind set. I was skeptical so spent the next couple of months studying up on the cognitive functions and realised that my Ni descriptions were actually Ti. So was left with either ISTP or INTP (both were relatable as f) . It's frustrating since I wanted accuracy and didn't want to just settle on any type.
The best way to go about this is to not focus on stereotypes/behaviour. You could act like an INTP but actually might be an ENTP, or an act like an INTJ when you're in fact and INFJ. Toss that mind set aside, keep studying the functions, apply them to how you go about in life and eventually you'll find your type. Takes a lot of time and introspection but you'll get there
I'm 19 now and finally realised I'm an ISTP so it's safe to say I'm finally satisfied. The INFJ mistype was probably due to my enneagram 9w8.