First - Congrats to you and to them
Now - step back, take a deep breath. Breath in. Breath out.
Now,
how many dresses total?
Can she or someone help making them? Even doing the cutting out of the patterns, the finishing work, hemming, embelishments? etc.
Do the girls all live close so you can take their measurements to get the right sizes?
I'd keep them as simple as possible.
What other things have they asked you to help them handle? Don't over extend yourself. Be honest with her about the time it will take, the help you would like etc.
I'm a former wedding consultant so feel free to PM me with any questions you may have.
QuiltingGrannie
Phyllis