I reset my xbox and I can't change my restriction settings

i just bought my game system and set up my account. I tried to voice chat while playing fortnite and it's telling me i have to change my privacy settings in order to voice chat. When i try to change the settings my xbox says i need an adult to sign in to change the settings. I'm the only one on my xbox and even factory reset it again and i still get the same thing. What is going on and/or what should I do?