Should I tell my gf this is what i think we should be for Halloween or should I make her watch the movie first

for added context: last year i was tammy and she was the t rex from tammy and the t rex. also my choice but she really like idea and i gotto go crazy in advance to recreate a very specific outfit. which i want to do for lola stone toobut I don’t want to be Couples Costume Boss. i mean i do bc i have great ideas but I don’t want her to feel put upon cgdffcalso important: she would look sooooo cute in a suit with fake blood on her face