Translation:I wear a white shirt.
But there was another question, I think it was "何のりょうりおつくりましたか?" Where Duo only accepted "what did we/you cook/make?" as a translation. That is, "what dish did I cook?" wasn't accepted, even though the implied subject should've been 私/僕 like you said. Gosh this is confusing. : (
In Japanese, the subject can usually be assumed. So unless the context makes it obvious, a statement should use "I". In the same vein, when you're asking a question, you don't usually ask yourself a question about yourself because you already know the answer. You are usually talking to someone, so "you" is the assumed pronoun.