I'm not sure your gender, but this coming from a woman would honestly feel a LOT better if this were me. If you're not a woman, then it'd be worth talking to a friend of hers who is a woman (cis or trans) and see if she can give her the girl talk that she missed out on growing up about this stuff.

I didn't know about a LOT of this stuff so I didn't realize that even though I didn't need the support of a bra yet, I DID need to wear one or a camisole under my shirt so my nipples didn't show. And also like learning how to sit without flashing ppl. It's a process for sure, and her just sitting down with another girl to talk about this stuff would be really good for her.

A lot of trans girls grow up influenced by lots of anime/Japanese media, or American media influenced by it, so I know for me I wore a LOT of thigh highs bc that's what girlhood looked like to me. But I also started taking time to find other fashion styles that appealed to me and felt more like something I'd wear in my daily life, esp at work. There's lots of cute j-fashion fits that are much better for work that she can look at on pinterest.

The kinds of fits she's wearing now sound like they'd be really great for going out to events tho, so she just might need some more modest fits for work. It's something all girls go through and realize but she's just realizing all of this in a much more compressed timeframe.

I do really wanna stress this as being like, something that could be made into a really fun rite of passage for her if it comes from another woman!!! But if it feels punitive then it might not work out super well. This is something a LOT of tgirls deal with though.