If you grow, or have direct access to fresh peas or other vegetables, this article is not for you, as their flavour, goodness and texture will be unsurpassible.
However, freshly picked vegetables lose 20% of their vitamin C within one day of picking, whereas, those frozen are generally processed within 2-3 hours of harvesting. The freezing process arrests their metabolism and retards the microbes that cause their decay.
Also betacarotene, an important antioxidant that's processed by the body into vitamin A, is destroyed by light. Because of this, all frozen vegetables can contain as much as 60% more than their fresh equivalants.
To maintain as much nutrition, whatever type of vegetables you cook, microwaving or steaming preserves more goodness than boiling, when a percentage of vitamins and minerals are lost in the water.