am i being a bad bride?

let me start by saying, i love my bridesmaids. LOVE them. they are my 3 best friends in the world, and my one and only little sis =) so i want them to look, and feel, beautiful on my wedding day.

i've already picked out the dress, a simple black, cap sleeve ruched black taffeta number....gorgeous, and totally rewearable (no really, my sis already has plans for it!) dress. and i've already told them i don't care how they get their hair done, or what shoes they wear, as long as they're black, or silver. for the record, my color scheme is pewter grey, lime green, and black and white. so black or silver shoes would be gorgeous, and totally appropriate. and i thought i was cool with that.

until today.

would i be a terrible bride for taking it all back, and asking them to wear one of these pairs?? they're lime green, and a pop of shoe color with their black dresses would be SOOOO cute, and since i'm wearing colored shoes too, then it would be even cuter!

my concern is 1) i'm not sure 3 1/2 to 3 3/4 inches is too high for them....i have some less-than-heel-loving girls....2) what if they are SUPREMELY uncomfortable??

what's a girl to do. i haven't voiced my desire for green shoes, because i didn't want them spending a lot on shoes they'd wear once. but THEY'RE BOTH LESS THAN $20 A PAIR, from GoJane. and they're soooooo fun.

help please!