mikijo's Pink wedding

Casey for sure knows who most of his wedding party will be. He has three other brothers, so picking his side will be easy.

Best Man: Colby, brother of groom
Groomsman: Cody, brother of groom
Corey, brother of groom
Jordan, cousin of groom
Mitch, friend of groom
Sean, my brother (I think they've spoken 10 words to each other but it means alot to me!!)
Ring Bearer: Collin, nephew of groom
Ushers: Jeremy, cousin of groom
Steve, friend of groom
Brett, cousin of bride
Bo, cousin of bride

As for my side...that will be a little bit more difficult. I would really like to name my mom the MOH because we talk at least once a day....but I want her to be able to sit down during the ceremony....so I may make her an honorary MOH....is that dumb?? I mean, I've never really had a girl bestfriend.
After that I really don't know...as of right now...this is who I think I'll ask....
Ashley, friend of bride (brother's gf)
Lauren, friend of bride
Alison, friend of bride
Michaela, friend of bride
Kelli, friend of bride
Nikki, friend of bride

How soon do I need to be asking them?? Within the next month or so??