Actually, i think that it does matter. I think that the US prizes aircraft carriers a lot. Its a kind of national status. For example, an attack on the carriers is considered an attack on CONUS.
Not that i think that it will be longer, but if china was to make an aircraft carrier longer than any ship of the USN, even if it is conventional and with less displacement, there would be offended egos on the other side of the pacific. And more calls to make bigger ships and navy.
Would that make any difference to china if it happened, i dont think so.
The idea that the USN would seek to build a larger carrier just so it is longer than 003 out of spite is a bit silly.
If 003 is somehow a bit longer than Nimitz or Ford, it won't be by more than a few meters at most, and the overall ship will still displace less as well.
That's why I say whether the specifics of the length are a couple meters longer or shorter than Nimitz/Ford, it really shouldn't matter to us, unless one is obsessed with literal size comparisons and the bragging rights associated with it.
At this stage in 003's construction there are many things that are much more interesting to await than the specifics of what its length will be -- confirmation on the number of catapults, elevators, the configuration of the flight deck, the size of the island, etc.