Do you really need to get bridesmaid dresses 6 months out?

Our wedding is in May and I went shopping with 4 of 6 of my girls last October (so, 7 months out). One of the other girls went in Novemeber and the last one was in December. Most of them took about 2 months to come in (we ordered through David's Bridal), but one of them took a little over 3 months. It's always good to make sure you give your girls time to get alterations done if needed, too. Another thing to consider if anything is going on near your wedding date... for example, my wedding is the same day as two local high school proms so that plays a factor in how much time it'll take to get dresses order and alterations done, as well as selection. But, I don't think you should have that problem in October!