When talking about female anatomy, it’s important to differentiate between the vagina and the labia minora. The vagina is the internal muscular canal that leads from the cervix to the outside of the body, located near the urethra. It’s not visible from the outside.
In contrast, the labia minora are the smaller, inner folds of skin that are part of the external genitalia. These, along with the larger outer folds called the labia majora, are what you can see externally.
To help understand this Better,
think about the difference between the anus and the buttocks. The anus is the internal opening through which the body expels waste, while the buttocks are the external parts you can see. Similarly, the vagina is internal, and the labia minora are part of the external genitalia.
Just like your Wudu will break the moment your bowel movement (e.g. the waste) reaches the outer edges of the anus, likewise your Hayd will have commenced once the bleeding has reached the outer edges of the vagina opening (even though it may not have reached the labia minora).