On Affirming Your Identity
No one, not even a legal entity, can tell you who you are, only you can tell yourself who you are. You may need to play along (like on legal forms) but that doesn't change you.

I always hated my birth name. I don't believe it was completely due to being trans.† It felt ill-fitting, like something itchy and hot you wore to a family gathering you didn't want to go to as a child. It doesn't help that I associate that name with a lot of bad memories.
I was yearning to be someone else before I made the announcement on my personal mastodon account. I don't know how to describe it, I just kept having this thought. "I want to be Jude!" "Can I be Jude?" and so on like that. So early in January of 2022, I tried the name on, online. It was well received. The only real problem was that, as I was not ready to try it with my family, I had no way to be sure it was for me.
So when I noticed a good excuse to write into the Bad With Money podcast (the excuse was about soliciting suggestions for something, I want to stress, I do not write into podcasts for minor corrections about nerd shit or something), I had the chance to sign it "Jude (they / them)". Honestly, at least of the podcasts I was listening to, it was the perfect choice. Naturally super-queer audience. And then I was lucky enough to hear my email read on the podcast. And when I heard Gabe call me Jude it was perfect and I believe I did cry that day listening from happiness. (Note: Due to legal reasons with an NDA Gabe signed after a breakup, I know some episodes were deleted from the podcast feed, I do not know which ones, but this may have been one of them). So while I'd love to say "it was the love and acceptance of my friends that got me to settle on a name" the truth of it is no it was senpai noticing and affirming me (to use a really outdated meme, but I love this meme dammit) that lead to my metaphorical rebirth.
Eventually I got my family to agree to use Jude, though first I had to re-explain the concept of Non-binary identity and such to my mother (ProTip: when doing this with religious relatives, have some religious or at least spiritual reasons. My mom admires the Quakers, so I brought up Public Universal Friend, for example). It took a lot of practice, and there's a couple complicating factors. For example, my stepmom seems to have some form of dementia, and I'm pretty sure half the time she thinks I'm still an eight-year-old, but whatever: I will play the role of the dutiful daughter to her on the phone as long as I have to, if only to thank her for some majorly helpful stuff she did for me throughout the years. And of course the fact I have not legally changed my name. I'm pretty set on being Jude, it's more costs-aside, this seems like a really bad time to change my name.
I acted in High School. I did not get major roles (I get the impression it was that most plays the school did didn't have a lot of roles for girls, and also there aren't a lot of roles for fat girls), but I am familiar with the concept of acting.
So I act the part of the old me when I go out in public. Thinking of the world as a stage and I'm an actor works best for me (though it gets a little uncomfortable when I think of the panopticon aspects of the modern day). If thinking about LARPing as your legal identity works better for you do it that way.
I wanted to add some suggestions for things (some tried, some not) that might help affirm your name and gender identity.
1. Write into a podcast that either responds to emails on air or at least replies to them. This is basically free, reminder: don't be a pedantic jerk, it doesn't really matter if someone mixed two X-Men; it especially doesn't matter if they correct themselves in the show notes or 30 seconds later. As a rule I recommend if you are replying in regards to a particular episode at least listen to the whole episode.
2. Ask a friend to start a call with discord or something and call you via microphone your preferred name.
3. If you're going to buy a book anyway, see if there's anywhere you can get it autographed with your name. I have bought two Ngozi Ukazu books (and yes I am buying Flip) from a particular bookstore because I could get Jude in text. I am putting this down because it did mean something to me, but as a rule please don't feel like you have to spend money to be who you are.
4. A Grounding exercise I often use from "You Feel Like Shit" has you state aloud to yourself: your name, age, location, and some things you have done today or will do today. Use this opportunity to state the name you WANT to be called the name you ARE.
5. Assuming you can write by hand, take a moment and just write your preferred name and pronouns a few times. Practice it as your signature if you want! You do not need to keep the paper or make it look nice if you don't want to or cannot. I suggest by hand because I had professors that were adamant that note-taking by hand versus note-taking via laptop is better for solidifying information (distractions aside). If you cannot write by hand, I am sure there is a way to adapt this exercise to work for you.
No one, not even a legal entity, can tell you who you are, only you can tell yourself who you are.
You may need to play along (like on legal forms) but that doesn't change you.
†: There is a story to my coming out, beyond what I shared here, but I think it's a story for another day.