Last time I bought small electrical parts from there, using China Post. Took about 1 week from delivery date to reach my door step. Quite fast for normal air mail.

I think dress wont have problem with kastam tho..

Anything can happen..I wouldnt relax coz if you need it on 11th which is still consider lucky if can reach by that time. If late than cannot blame also since is still within expected arrival date. Even they reached early but if Pos Malaysia themselves kacau keep delay also how..

Wish you luck