Answer:
Curtail me thrice I am a youth; behead me once a snake; complete I'm often used in truth when certain steps you'd take.
What is it called when a cat wins a dog show?
What can fill a room but takes up no space?
Although a human shape I wear Mother I never had; And though no sense nor life I share in finest silks I'm clad. By every miss I'm valued much beloved and highly prized; still my cruel fate is such by boys I am often despised.
I follow you all the time and copy your every move but you can't touch me or catch me. What am I?
A little house full of meat, no door to go in and eat.