I ve never have , whene i do for the first time i don't feel pain and i find that i already lose my hymn.?

I ' ve never have , but when i do, i got surprised to know that i already lose it ; maybe i born without it or i lose it while doing activities , i don't know really how ? i don't remember i bleed out of my period . I wonder why i feel no pain while having for the first time ?