Ladies, what age did you discover you had a hole in the front distinct from the one for urination?
I'm not entirely sure but certainly by my mid teens I fully understood it's purpose and had viewed the opening with a mirror. I tried to put an empty tampon tube in it to see how penetration felt but it was too painful and wouldn't go in.
It got looked at during my first gyno exam, she pulled the minora wide and didn't do the test as my hymen was intact.
I felt my first insertion into it aged 21 when my first gf forced 2 fingers up it. It hurt so bad I squealed in pain. I love to get fingered now though so I've come to appreciate that opening!
Read here more information what is bonus group membership.