Firstly, congratulations on your virginity... though not familiar with the variety you're growing, if it's a 'slicer' rather than a 'pickler' then they should be picked at about 6 to 8 inches long although they can go to 10 inches or so and still be platable. A tip... if you are growing table or salad cucumbers, try raising them on stakes. Just tie them up to good stout stakes that are at least 5 feet tall. I use brown twine to tie them as they grow. The cucumbers will grow straighter and I believe taste better. They're also easier to pick. Picking young or early samples of the other vegetables you mention won't impair the taste. In fact, the young carrots have a more intense taste than older ones. Good luck!