The definition of these "generations" is arbitrary and subjective. The reality of the matter is no such person exists. So, I completely disagree.
Even if everyone in the world agreed that Gen Z is all people born between 1995 and 2010 (which would require you to be ignorant, naive, or just plain stupid), it ignores the reality of things like geography, culture, time zones, etc. Literally hundreds (if not thousands) of people could have been born at the exact same moment of time, but due to the magic of time zones, some would be Gen Z, others would not. That's super arbitrary if you ask me.
So, it's more like theoretically some person is the oldest member of Gen Z, for some given interpretation of what "Gen Z" means. But in practice, there's no such thing. In some ways it's like a mathematical limit. There's no smallest number greater than 0, because you can always devise a smaller fraction. But, if you artificially and arbitrarily limit your resolution (let's say to 1/10th), only then can you declare some number the smallest (ex: .1).