Tomatoes may change color after you take them off the plant but they don't develop that wonderful flavor that they have if you let them ripen on the plant. It takes sugar that they get from the leaves photosynthesizing to put the flavor into the fruit.
I would wait. I think the sunny weather, and long days of June will have your tomatoes turning red very soon. But yes, beefsteak type tomatoes do take a long time.
