I'm not trying to disparage OP's experience and accomplishment, but just trying to give a counter PoV for casual HN readers on the subject.
As many sibling posts have already pointed out, passing JLPT is not trivial for many people. Also N3 level is (IMHO at best) intermediate[0] proficiency and still quite far from fluency. Here's an example of "random" Japanese grade schoolers solving JLPT N3 questions with ease.
That said, just like any subject, language acquisition talents vary from person to person, and no doubt OP is among the more gifted.
tl; dr: do not introduce yourself in Japanese with "waga na wa [name]"[2].
[0] https://en.wikipedia.org/wiki/Japanese-Language_Proficiency_...