So overall the costume is beautiful and very accurate, a little hard to put on the first time (check the tutorial and do it as the same time when put it on), some part were big for me (the belt especially was way to big and the top a little but it'ok), but the pant fit nicely at least.
There isn't many part to pin (unlike some other genshin cosplay), be careful at your vision, it's heavy so the pin is not holding well (and it can break when it fall on the floor)
I am 178cm for around 60 kg, i took L size