How can a girl be a non-virgin?

On tuesday I found out that I am not a virgin while I never had sex before.How could that happen?

In addition to puffin200's answer, don't let that make you feel like there's something wrong about it. Our bodies are all different in many ways. A hymen is just an indicator of virginity but not the defining factor. In every way, you are a normal virgin.

Some girls don't have hymen by birth or sometimes it couldbe broken while doing sports.

When Yhu Love Someone Or Like And You Would Do Anythinq In The World Be Be Or Keep Them