mouse click condition

how can i check that mouse clicked three times.
void OnMouseDown()
{
if (transform.childCount == 0)
{
SceneManager.LoadScene(1);
}
else if(transform.childCount==1)
{
Destroy(gameObject);
}
i want to check 3 gameobject destroys.than i wanna move to next scene.

Destroy(gameObject);
This line destroy the GameObject, including the script and the childrens

void OnMouseDown() {
    if (transform.childCount == 0) 
        SceneManager.LoadScene(1); 
    else if(transform.childCount==1)
        Destroy(transform.GetChild(0).gameObject);//Destroy the first GameObject

}

how can i go to next level if 3 objects are destroyed.