I just got a semi-angsty, semi-sweet idea for the trans!Danny headcanon.
Jazz wasn’t always accepting of Danny being trans. Whether it was that she was mad she didn’t have a little sister anymore or society’s general transphobia got to her, it took her some time to come around.
Later, when Danny has his powers and after he learns that Jazz knows, he asks her why she supported him being Phantom even when, for all she knows, he actually did kidnap the mayor and rob a bank.
Jazz takes in a deep breath, and her eyes get a little teary when she tells him, “I took too long to accept you for who you are before. I’m not making that mistake again.”