Does it start chattering a lot at high speed and do you find you skid too easily when you turn? If so, you might be a bit heavy for the board.
Length and recommended weight increase together but provided you are within the weight guide, the length of the board is mostly personal preference. I'm 5"8 and did have a 152 jib board which was fun and a good ride but I'm much happier overall with a 156.
Perhaps you could try hiring a longer board to see how it works for you? It won't ride the same as your flying v (unless you can hire a flying v of course) but you'll get a feel for whether you prefer having a bit of extra nose in front of your leading foot.