"I've recently been told it's wrong to start a sentence with numerals; i.e. "5235 Western Road was a big blue house..."
Who are these schmucks running around playing fast and loose with the W word — "wrong" —and thereby messing with the heads of writers seeking simple, useful guidelines? Why is it that, in a culture that is so profoundly immune to facts (Bill O'Reilly could say the stock market hit 13,000 today but the liberal media is lying about it and many would believe him; the Washington Post could run a cover story saying Obama is funneling money to a funnel manufacturer and some would simply dismiss it as a lie), people take language/grammar hearsay as gospel?
These things are not a matter of right and wrong. They're a matter of style. AP says to write out numbers at the beginnings of sentences, except when they're years.
"Twenty-three children will graduate JoJo's dance class in 2021"
"2021 should be an interesting year."
Chicago doesn't share AP's view that there should be an exception for years. At the beginning of a sentence, you still spell out the year, per Chicago.
"Twenty-three children will graduate JoJo's dance class in 2021," BUT
"Twenty twenty-one should be an interesting year."
For anyone looking for a simple guideline: Yes. It's probably best to avoid numerals at the beginnings of sentences. But that's just because two major style guides prefer it. Not because of issues of "right" and "wrong."