LW? Your sister is coming to terms with a fundamental life-changing circumstance (particularly if Mariah is her first), as well as recovering from a demanding physical ordeal and in a state of hormonal volatility; right now the last thing she needs is you piling on the specter of future adolescent rebelliousness. Particularly if it comes across as laying a curse, however facetious, on her child; you just turned into the Wicked Fairy At The Christening.

(And Deputy Mom is a common life script for oldest daughters; don’t be surprised if that’s how Mariah turns out.)