A personal opinion, so take it as you will: Your bum and thighs are lovely. I am not trying to soothe you, rather telling you what I see, if that makes sense? To have posted, you are open to answers, and this must have taken a certain amount of courage.
You look feminine, not a word that seems to be trending right now, but it's still a thing, a human response, a cultural by product. And by feminine, I mean attractive, toned, shaped, healthy, slim.
I was there once, too. What I came to feel is that life is way, waaay too short to not allow oneself to dress in a way that pleases and inspires you. Far too fucking short! We can make allowances for mental health issues, confidence levels and so on, but that still won't make life any longer. There's this one shot, and we won't receive a trophy on our death beds for being too careful, self deprecating or self loathing. I say this to empower you, not to flatter you or dismiss your personal pain.
Hearing 'people would kill for those legs' won't alter the shape of our self loathing, even if for a few seconds we soak it up with pleasure. But people surely would kill for your legs, and bum, and you look exquisite in that skirt.
We are all so very different, in age, physique, diet, lifestyle, proportions. We are nose led by a media image of what might be desirable, but this changes like quicksand, it isn't worth the agony for 5 minutes of personal satisfaction. We need to breed this regardless, as the framework for our lives.
I recently took up yoga, it has altered the way in which I view my own body - a body that will age (I am late 40's) and sag and be open to illness to some extent.
But nothing is a given. I am not opposed to a touch of woo either: a lot of what we firmly believe tends to get borne out in our experience.
Perspective does help with dysmorphic feelings. Imagine holding yourself back, not wearing the kind of make-up you'd love, that would be an essential expression of who you are.........and then the world ends. Or we suffer loss. Or we encounter disease or disability. It does help to reign our thoughts in this way.
However, if you will forgive the waffle, you do look quite lovely. Own it and grow into yourself. And enjoy your body as best you can 