There is no "I" in "You"

[quip]

Or alternatively, Can the atheist rationally avoid the inquiry by simply asserting that there was nothing "prior to the established "I""?

There is nothing 'prior to the established 'I''. The existence of the brain that generates 'me' determines 'my' existence.

If there is nothing prior to the established "I" then wherefore the determinate factors denoting your particular quale in distinction to roughly six billion alternate, extant possibilities?