How do you know what's your element?

Answer 1

Are you asking how you know what element a given sample of material is (assuming that it is, in fact, an element and not a compound or mixture)? If so, there are various chemical tests you could run, but in actual practice it's almost always easier to do a spectrographic analysis.

If you're asking about "your element" in some sort of new-agey Astrology analogue... beats me, I only know about real science.