Cis person with many trans friends who experienced the same kind of problem, hope it's okay for me to chip in.

The advice I wish I could've given them is that it's okay if it takes time for you to understand how you want to present your gender, or if you go through a few identities before settling on one that feels right for you. One of my best friends, when I met her, she was masc presenting non-binary and using they/them pronouns, then she considered herself a binary trans woman for a while (and started medical transition), but that wasn't quite right yet, and now she identifies as a non binary woman. I remember each of these internal transitions caused her a lot of grief because it meant re-coming out to the world, and she questioned the validity of her own gender.

If an identity or a way of presenting to the world is a stepping stone to something new, it's not necessarily an "incorrect" label if it helps you along the way. And even if something is incorrect for you and doesn't speak to any version of you, that's chill, it doesn't diminish the significance of the version of you that you feel comfortable being and presenting to the world, no matter how long it takes to find the point you're comfortable in.

I had another friend who stuck with a name that she hated for like a year, because that was the name that she'd told everyone when she did a big coming out and she felt weird "retconning" that. When she eventually stopped torturing herself by sticking with a name she came to hate more than her dead name, she picked a new name and did a small "trial run" amongst her close friends for a few months, to be sure that this time, her name felt right. She told me that she jumped into the name and the personal style stuff too quickly, because she had started HRT and figured she'd had to come out soon anyway, so she needed to have a complete idea of the woman she'd be from the outset, which led to the premature name choice.

And speaking of style, one of my transmasc friends lived for most of his life identifying and presenting as a pretty archetypical butch lesbian. Shortly after coming out, he went through a phase of trying to be a super manly man, because it turned out that his gender presentation was already pretty spot on for where he wanted to be, he just wanted the world to change how it viewed him (in his words, "genderqueer soft boi, rather than spiky dyke"). He explained to me that from the start, he sort of already knew he didn't want to change much about himself, but he felt obliged to mark this as something different from the flavour of gender non-conforming he expressed before, as a lesbian.

The core theme here is feeling pressured to do or be stuff that isn't true to oneself, and I don't think I'd even call these stories "mistakes". A lot is going to change, and the world will look very different to future-you in ways that you can't currently imagine and that's not a bug, that's a feature. It was a rockier journey for some than others, but all of my trans friends are in a better place now than when they started, even if that wasn't what they expected. You'll be facing a lot of pressure from so many sources, whether that's the trans community, shitty transphobes or well intentioned cis folk, and it's not unreasonable to need time to properly process it all and figure out what you want.

Just try to be kind to yourself throughout it, even when the world makes you feel like you should be more than what you're able to be - especially then. You don't need a crystal clear understanding of The Plan (Tm); sometimes a vague direction away from or towards something is enough to get you going.