"A billionaire" is defined by having a net worth > 1 Billion USD, in July 30th, 2023 inflation adjusted dollars. This question resolves to yes if any of the 32 members of the July session become a billionaire before they turn 31 years old. The duration of this net worth can be whatever, but all valuations need to be credible. For example, if a Fellow mints 500M crypto tokens and sells 10 of them at 2$ each, this doesn't count.