Many varieties of fruit should not be grown from seed and Grapes are one of them. Seedlings exhibit an inherent variability that means the new tree or vine you grow won't 'come true' as the old timers say. Grapes are so variable that you could plant hundreds, or perhaps even thousands, of seeds and not find an offspring that resembles the fruit desired.
Grapes are propagated asexually via layers, cuttings or they are grafted into root stock that in turn were propagated asexually. If you are serious about growing grapes you should look into either purchasing vines or taking cuttings soon from an established vineyard.