Don't get me wrong - I'd love to be able to do dd's hair like XXX mum. Or to have a lovely going out wardrobe like XXX but none of it matters. I'm sure there's things about my life that they covet too. It's normal.
I think in today's world of curated lives via Instagram/Pinterest/Facebook it's quite normal to feel like you don't always measure up. But as long as your children are loved, well cared for and happy, all the rest is just window dressing
Maybe she's just really into style and aesthetics and it comes naturally to her? I love thinking about/planning and styling, but this is part of what I do so it doesn't seem like an effort, if that makes sense. There's lots I don't know about but style and what goes together comes naturally to me. The same with my home and my DC, but as I said, I just really enjoy it.
In terms of kids clothes, the French and Spanish brands are great but we have some great home grown brands too (Rachel Riley, Hucklebones, Nicki MacFarlane for example). My DC takes after me with regards to style and has very strong opinions about clothes already!
Don't worry about it, I'm sure she doesn't and just enjoy being her friend. I'm sure there are many things in you she values that comes naturally to you. And as far as the social media stuff goes, it's an image only. I don't use any for my private life but do professionally and believe me, it's the best way to provide a doctored image of your life, if you so wish.
nrtft but, from my experience of European living, clothes tend to be quite stylish, yet expensive and with limited colours. It could just be that they've fallen into that mode of dressing/living since being out there. Give it time and they'll be British dressers again; I.e. quirky, creative and colourful.