Just basing it off her topline and waist area, I would say she could stand to lose some. Then again, she may not be done growing and that weight could be perfect for her once she's finished. I preferred to keep Ace on the skinny side even when he was younger, as he was so incredibly active and fond of running and jumping that it just made sense to keep him slim.
I agree she could drop a few pounds, but since she's still growing I would bring her down fairly slowly.
Is she on a high-calorie food? (Blue has several varieties). Since she's only getting 2/3 cup a day, you might find a version of a food you like that has closer to 350 cal/cup rather than reducing her further, and just switch her gradually.
These are great pics. If you read the other thread on weight, you will have seen that I mentioned the topline is a better indicator of a Corgi's weight than whether or not it tucks up. From the side she looks ok but when you look just at her topline you can see the couple extra pounds.