However, this first sentence works.
We have a person – "I" – and a location – "the lobby of the Waldorf-Astoria." We have a problem: "found a baby." We have a time stamp: "When I was six years old." Let's take those elements one by one.
"I" tells us that the voice we hear now will be the voice of the book. It's a graceful voice. This sentence rolls with several natural breaths in its structure. I'll break it with /s to show the clauses: When I was six years old, / I found a baby / in the lobby / of the Waldorf-Astoria. There's an understated internal rhyme between "baby" and "lobby" – most often, when rhyming words that end in unstressed syllables, the rhyme includes the vowel of the penultimate syllable and everything that follows it. That would give us the more obvious rhymes of "baby" and "maybe," or "knobby" and "lobby." The ear picks up the matching consonant and last vowel of "baby" and "lobby," but they call less attention to themselves than the longer rhyming portions would.
The longer starting and ending clauses with shorter clauses between is also a poetic structure.
"The lobby of the Waldorf-Astoria" is a precise place. The baby wasn't in a room, where one might expect it. The Waldorf-Astoria is an upscale hotel, where a lost baby is both more unexpected and possibly more fortunate than on the doorstep of a church or orphanage or in a dumpster. Do you see how we've already heard those stories and how they suggest grimmer outcomes? Waldorf-Astoria gives a bit of lightness and a bit of surprise – well-placed as the final word in the sentence.
"Found a baby" is a problem because babies should not be lost. Babies should be attended, even more carefully than the rolling cases and backpacks we take to the airport.
Finally, "when I was six years old" doesn't necessarily mark the current time of the sentence. The narrator's voice, with its precision and moderate length sentence, is an adult voice. So the narrator is looking back. However, to find a baby at that young age suggests both early heroism and a clue to the shape of a life. Since this is the story the narrator starts with, that baby left a mark. "When I was six" begins a personal myth as "Once upon a time" begins a folk story.
This is a great first sentence.
Graphic design by Ken Silbert