actual things you can do to keep yourself safe online instead of relying on a dni:
don't use your real name! not even your first name, if it's unusual!
don't tell anybody where you live! not even what state you're in! keep that shit a sexy little mystery that's between you and your mail carrier!!
liberally use the block feature!!!! use it!!! just block people if they give you the heebie jeebies!!
don't post selfies that you've also posted on facebook or anywhere else! reverse image search can be used to find your name if the same image is tied to fb or insta or anywhere else your actual name might be
consider not posting selfies at all actually esp if you're a minor......., shit can be dangerous
there's no reason you have to advertise your age if you're a minor <3 you don't have to tell anyone! don't lie, and please don't interact with 18+ content, or with adults who are uncomfortable with people under 18 interacting--but you don't have to go out of you way to say on your blog "hey I'm a minor and a member of a vulnerable community"! and if someone asks then you are allowed to tell them to fuck off
tell people to fuck off if they ask you questions that could be used to identify you