Leave them as long as you can, you can eat the immature fruit, even if very tiny, I have collected a pot full of babies no bigger than a tiny new potato and stir fried them or steamed them whole,you can even eat the blossoms, they are good stuffed. Bear in mind they will not keep like their big brothers and used to be used. Also bear in mind that most pumpkins don't have the flavour that some other squash have. XX Jeannine