Wait, so it doesn't output ooooooooooooooooooooooooooooooooooooooooooooo? It doesn't sound like it's a mobile keyboard...
Ist ja auch nicht falsch. Nur ungewohnt.
Oh, definitely. It varies depending on the context, I think. If you say "das Mädchen"/"ein Mädchen", some part of us parses that as grammatically neutral instead of semantically female, and saying "sie" sounds weird. At least in the same sentence, because it's part of the same structure. But there aren't a lot of contexts where it is used non-descriptively, so something like "Ein Mädchen ist anders. Sie ist kein Junge." has much more emphasis on semantics for me in the first sentence.
What might make it less of a big deal for me to break the rule is that I grew up with two dialects, both of which use "et" (meaning "es") or "es" instead of "sie" and "die" in some cases. "Das Mädchen", OK. "Das Michelle" instead of "die Michelle" (which in itself is not proper German), OK. "Michelle ist blöd. Es hat mich gehauen.", OK.
(Apparently, the German dialect on the other side of the French border does the same thing.)
OK, wait, I found what Duden has to say about this. Usually, it's "es". But if the pronoun stands apart far enough, it can be "sie". How far? Well... that's up to us. Personally, "Das Mädchen spielt mir seiner Puppe" sounds really weird and I prefer "Das Mädchen spielt mit ihrer Puppe". Far enough for me.
But that's not really the issue here. The reader doesn't know that the sheep ("das
Schaf") is male, so they might expect an "es" instead of an "er".