Why oh why do designers have to have different colors

Ok so today i went with moh to order her dress. and that process wient smoothly. then of course i do the thing i always do and that is second guess my color. I am doin the davinci 9019 and that royal blue seems duller than another royal blue. but i love the dress but wondering if my color is going to wrong. i dont know what to do now considering moh placed here order. they did say the order couldnt go through untill all 3 bridesmaids came it to place order. so i guess we will see what happens. am i just a nerotic bride?