Hello Ladies. I hope you're all having a wonderful night.

One of my bridesmaids it planning on having a baby! And I'm excited for her! But I have two issues:
1) Since she in not yet pregnant and does not know when she will acutally become pregnant or how far along she will be around the time we go to order the other girls' dresses when do we order her dress?? We are getting married in September and getting the bridesmaids dresses from David's Bridal so should we go in early August and order a somewhat bigger size??
2) She called me the other day and said the wedding was in September she wanted to let me know that it may be cold or it maybe hot and I should think about changing the date of the wedding. Because she wants to be comfortable if she is pregnant by then. How do I tell her that I am thankful for her advice but I'm not going to make changes for her like that just because she is pregnant. (And no I don't talk to her about the wedding everytime when I talk to her, if she asks I answer, other no.)
I have consisder getting cardigans for the girls just incase the weather is a bit chilly.
I did mention in one of our converstations that if she is pregnant I want her to be comfortable (since the girls will be in heels and short dresses for most of the day). Soon after I got the phone call about changing the date. And she would like me to take that into consideration for her.
Thanks Ladies!
-L