Vopmocld Big Girls' Lovely Sleepy Panda Sleepwears Cute Cartoon 2PCS Pajama Sets - Pink - Large/9-11 Years

The sizing is certainly confusing. Would the size X-large (15-16yrs) be equivalent to a women's small or medium?

The child i am buying for wears us girls size 10. would i order a 10 in these or bigger? thanks.

Are these flame retardant free?

Does this ship in the United States?