congratulations it really is a lovely plant and it is a bonus when you actually get a fruit as well I don,t know much about the fruit the only thing I remember is that they take a long time to ripen . Why don,t you get one from the supermarket and then you can compare them.

When to harvest depends what kind it is. The common blue or pink flowered passiflora produces a yellow fruit that you pick when it is soft in your hand. The seeds and pulp around them are edible, but don't taste of much, unlike the "proper" edible kind which I believe is from a different sub species of plant. Wildlife are fond of them too

PS better not to try eating them if you or neighbours have used weedkiller or insecticide not specially licenced for use on edible plants!!

It depends what sort of passion flower plant you have - I bought one a year or so ago, that got loads of "fruit" but they were hollow and inedible, check with your local garden centre.

From a fellow grower: Never pick a passion fruit when it's green and unripe, it will remain inedible. There are many kinds of passion flower vines, and all of the fruits are edible. Even the 'banana passionfruit' which has a completely different flower. The most common passion fruits here turn yellow when ripe. But some varieties turn purple. Passion fruit makes a delectible salad dressing!