Mei's Dress Dilemma

Mei will always be my baby cousin.  Which makes me want to dress her up in something with cap sleeves and taffeta.  I know she's 16, but I don't want to scandalize her (and yes, I do realize there are MUCH more scandalizing things she sees every day in a public high school than a strapless dress, so maybe the word isn't so much scandalize as...ummm...tart her up?...)

In any case, we're going to get her dress today, and so I'm frantically searching for a dress with straps.

Here's one that I've found... It has some pleats in it, which I was thinking she would still have like the bridesmaids, but it's got straps and a fuller skirt.  

Or something maybe like this, but with straps:

Or this one, again with straps?

Or this one, which is very similar to the girls' dress...but again with straps for the ceremony.