I am just under 5'4 so my height is fairly average/small, but as a teen I absolutely hated my body. I developed hips a good 3 or 4 years before I really got boobs. Looking back on myself I had a lovely figure but at the time I was so self conscious, I used to punch myself in the hips before I went to sleep every night in the hope I could train them to grow back inwards
. I also went through a phase of wearing really padded bras to try and even myself out on top. I was convinced that everyone else around me was normal but that I was some kind of deformed out of proportion freak (I'm sorry for my language but this is how I thought back then). I was constantly looking at my reflection in any surface I could... I got called vain for that a few times but I hated myself in an extreme way.
It definitely helped me to see women with similar figures. I remember when Shakira first came out and she had a line in her song about her "small and humble" breasts... it really helped my confidence at the time. It took me until I was much older to stop negatively focussing on my appearance so much. It wasn't until I got pregnant actually, and then when I breastfed and felt like "ahh so that's what these things are for".
I know my hang ups were not the same as your dd's but I think it's comparable. I really feel bad for your dd and for all young girls going through something like this. It's so hard to be a teenager, especially a teenage girl I think (I'm sure boys have their own insecurities) and there will always be something we are unhappy with. I think it affects some of us more than others. I was never sporty and completely lacked coordination, but loved the outdoors and walking. However, I got so much harrassment from men that it put me off! I do think that getting involved in something that uses your body for what it can do, rather than how it looks, is key though. At least that was my experience and I wish it hadn't been pregnancy that did it for me... But some kind of fitness outdoor hobby, away from screens I think could be very beneficial. A hiking group perhaps if she isn't into sports... I don't know, but I am sure there is something. I plan to try and make sure my dd is involved in something fitness/sporty/outdoorsy related when she gets older anyway.
One thing I will say is my mum used to get anrgy at me if I ever mentioned my insecurities. She'd tell me that nobody would notice if I didn't mention the things I worried about - which made me feel as though I truly did have something wrong with me that I needed to be ashamed of and hide (and going on about her big boobs and small hips did not make me feel better either!) I definitely think reassurance is better than dismissiveness, but also like I said, trying to refocus away from how the body looks and more on to what the body can do.
(Sorry this is such a rambly post... have been ill with a fever and am not sure I'm fully compos mentis!)