Princess variants!
If it's the one I'm thinking of then I am pretty sure she is real
I have seen plenty with a thin yellow tail with tinsel, but this is the first one I've seen without tinsel.
There are a couple of things that it could be including: the tinsel was brushed out (princess variants were terribly well made and often loose tails), the child pulled the tinsel out (I've had so called tinsel-less Princesses who on inspection has tinsel stumps where it had been snapped off) or she got a tail with out tinsel (this would make her new to the community).
Why do I think she's real? She has no forelock, the symbol is "correct" and has the round red jewel (this round red jewel is from 2nd set Princess Sunbeam), the tail is the right shade of yellow and appears to be the correct length.
In order to fake this princess you'd need a yellow haired Princess Pearl, Princess Amber and a Princess Sunbeam. Also taking princess symbols apart without trashing them is pretty difficult.
Love pkw xxx