What type of pea pod ?
We think this might be a snow pea, based on the thin margin at the edge.
Snow peas are generally harvested while still thin.
Take a look at this link: http://extension.umd.edu/growit/vegetable-profiles-green-peas
Can I still use the pods that are overgrown? Can I cook the peas as if they are regular green peas?
You can shell the pea and eat them as normal peas.If harvested young you eat the whole pod.