First Ace to Appear

There is nothing distinguishing the aces from each other besides their labels.

Think about the relative order of just the four aces within the shuffled deck.

1. 1. Symmetry argument

   Only the relative order of the four aces among themselves determines which is first, and all $4!$ orderings of the aces are equally likely under a uniform shuffle.

2. 2. Conclude

   By symmetry, each ace is first with probability $1/4$.

Answer: All four are equally likely.