fake it

Reader's　Digest 11月号の記事 "Adventures in Babysitting" からの引用です。

Fake It to Make It
I was 12 years old and doing a lot of babysitting. Once, I was left in charge of four kids. I asked them all their names and ages. Imagine my surprise to learn the first born was a year older than me. I was tall for my age and she was short, so I didn't tell them I was actually their "big" sister's junior.

米国では幼い子を家において親が外出することを禁止しているので、若い女性（たいてい女子中高生）にベイビーシッターを依頼するのが当たり前です。　記事の表題にある "Fake It" はいわゆるフェイクニュースの "fake" とはニュアンスが違うようなので、辞書で確認します。
・Merrium-Webster: to pretend to be something that one is not or to have some knowledge or ability that one does not really have: He acts like he's my friend, but I can tell that he's just faking it.
・Farlex Dictionary of Idioms: To act as though one is knowledgeable or competent in some area.: A: "I'm panicking and can't remember any of the steps to the dance routine!" B: "Then just get in the back and fake it!"
・Wiktionary: To pretend to be capable or competent.: He told me that he was experienced, but I could tell instantly that he was faking it.
最後に引用した辞書には "fake it till one makes it" という表現もある事が分かりました。
・Wiktionary: (psychology) To pretend to be a certain way until one becomes that way.
"Fake It" の表現は "fake it till one makes it" を基にしたのでしょう。