You said the pattern called for the blue for the border, right? That doesn't mean you have to go with that though.......I like the darker blue also, and I am guessing the pattern called for that because of the blue in the blocks. If you don't like the dark blue, why not bring out the green that each block is made with and do the border with that? Would that be too much green for you?
As everyone said, it is your choice.
Barb