Hi MarinH20,
My apologies for missing this thread.
Congratulations on your find!
The food oyster Crassostrea virginica is widely produced and/or occurs naturally on the east coast of North America. Occasionally, pearls may be found. I believe Cookes Cove oysters are dredged in the wild, hence not considered farmed therefore a true natural pearl.
Food oysters are not pearl oysters, having greater proportions of calcite than aragonite. Many are chalky in appearance naturally or become that way over time.
Your pearl presents as off round with a silver gray, somewhat (no highly) lustrous surface and appears approx 4mm in diameter.
While finding a pearl is a rare event, it does not imply high value. At P-G, we are reluctant to imply value although any referrals from members are legitimate collectors or retailers. It's a nice pearl, but not extraordinary, sorry to say.
As with most pearls of this type, my recommendation is retaining it as a keepsake. A lifelong enjoyment of finding and viewing a rare object is more often greater than selling at a low rate where resellers need to find even a small margin of profit.