I agree with the others. You still have 12 months to go and a lot can happen in that time. e.g. someone falling pregnant etc. Plus, as a bridesmaid myself in a few months, I wouldn't want my dress ordered so early. It puts a lot of pressure to have to stay that weight for a whole year!
We ordered ours at the 6 month mark - knowing it would take 3 months for them to arrive from designer in the USA. That still gave the girls 3 months to organise alterations and to get one dress to the UK. If my MOH did not live in the UK and I did not have to send her dress to her...I would have ordered them around the 4.5 - 5 month mark.
My girlfriend who is getting married early October ordered her bridesmaid dresses from the same same website - lightinthebox.com - and it only took the dresses about a month to get to Australia..that including the time it took to make all 4 dresses and postage from China. Super fast!