/cgl/ - Cosplay & EGL

I'm back with another dumb question
for the cosplay I'm working on I wanna add a fluffy collar thing both around the neck and the wrists
I think I have a way, but I'm just afraid I'm doing something dumb because I've not done anything this significant with sewing before
the way I'm thinking is cutting out the shape but mirrored, folding it across the red line, and then sewing it along the other edge
is this good or is there a better way?
thanks!