My lovely girlfriend struggles when it comes to fashion, advice welcomed!

A little background: (TLDR; dating an amazing girl who has no motivation for self-care/fashion, has had rough life) My girlfriend and I (male) have been dating for about 3 months. we attend and liberal arts college in the northeast, think almost as preppy as Ivy leagues (we are both white, and money is not an issue). I come from Norther California, and she from a rough town in the northeast. I love her dearly for all that she is, especially on the inside, but she seems to have very little motivation for her self-care (especially fashion). She used to play basketball in high school, but no more. her body type could be considered a little on the plus (medium) size (not obese, just a little extra as I like to think), and is self-conscious about this. Shes had a rough life (lost her oldest sister at age 5 in and accident that she was also in, dad has become verbally abusive towards her since then, but in good relations with mom and younger sisters, I am the only one at this college who knows this). She is a clam (quiet and doesn't like to talk about personal stuff) and while she has a tough skin, she can be set upset by very unpredictable things. She hates being compared to other people in any way (pointing out an article of clothing that someone else is wear that i think looks good is to be avoided). She is also first in her family to go to college. In other words, if you giver her a hard time about anything she tends to get very defensive. Don't get me wrong, I love her dearly (no, really, I do!) and she has way more awesome things about her, but they just don't help your understanding of the situation.

Current state of her dress: While I am not the most fashionable of males, I make a consistent effort to improve my looks. On the other hand, she has little respect for her self-care (she has directly told me as such). She considers me to be a much higher priority than taking care of herself (I very much disagree) She would be most comfortable wearing sneakers, baggy sweatpants, t shirt, and sweatshirt, preferably in school colors (one of which happens to be bright orange). I've gotten her to be a little more divers, bust she still ears at lease on of these items every day) Her wardrobe consists mostly of t-shirts, baggy sweatpants (before I met her this was her default, I've gotten her to wear them less often), a few yoga pants, some jeans, one pair of leggings, lots of sneakers, some new decent footwear (boots, flats, etc), one pea-coat, sweatshirts, and one big winter jacket.

I have gotten her to go shopping for some better clothes, and she does have an alright sense of fashion (it still needs help), but it mostly just seems to be that she doesn't think looking presentable is important. Obviously there could be/are many reasons for this, but its difficult to know. I've tried a few different tactics to help her, but I really want to help her help herself by giving herself the time and respect she needs to take care of her own hygiene, diet, and clothing. She has said that she isn't happy with the current state of things, but seems to kinda be stuck in a rut.

TLDR: Amazing girlfriend with rough background, stuck in a rut of little motivation for taking care of herself (esp. fashion, sweatpants are the norm)

Any advice on how to help her (or me?) would be most appreciated. Sorry about the absurd length. Happy to answer any questions