A literal translation might be "prendre quelqu'un sous ton aile." But the English version is an idiomatic expression that probably doesn't translate directly into French. So what is the closest French equivalent?
It is "Prendre quelqu’un sous son aile", see here, and is quite commonly used. Note that the version: "tu l'as pris sous ton aile" where emphasis is put on the agent offering protection is less common, but still correct and good sounding.