bridal party dilema

so one of those girls who i asked to be in bridal party told me she really doesn't have the $ for it, but yet shes not definitely stepping down. I was in hers in the beginning of august and we used to be really close until like April of this year when she started school at night. i have only known her for about 3 years. i understand shes very busy, but i felt like once i started planning my wedding she and i drifted apart. like i felt uncomforable around her at her wedding. I sent an email with pics of possible dresses to the girls in the bp (about a month ago) including her and everyone but her responded. so i emailed her are u ok? shes like well we need to talk, i might not be able to afford to be in ur bp. shes like my money situation is so different from when u asked me. b/c now shes only working part time, but then shes goes onto say that her $ situation might be different next year. and that feels so bad, and that shes afraid to commit to it now because if next year comes and shes still in the spot she will have to step down. so i sent her this long em back about how we're friends first and i won't be mad if she has to step down. so heres my dilema, i kind of hope she steps down cause i have another friend i'd rather ask( i have been friends with this girl for 10 years but around the time we got engaged we had an argument so i didnt' ask her), but i would never in a million years ask my first friend to step down. I emailed my bm today since she never responded to my email about me not being mad if she steps down and she worte back basically the same thing:
'i really can not let you know at this moment and i'm sorry. i don't want to tell you yes and then when it comes down to it, not be able to afford to be in it. financially, i won't know exactly where i'll be next year with everything going on, work, house, etc. if you have to give her an answer now, i guess don't mention me. i wish i could give you an answer now but honestly, i can't til i know what's going to happen later on. i can barely afford everything now. i haven't paid rent in months cause i can't afford it. i'm really struggling as it is. i hope you understand and again, i'm very sorry. love you too :)
Do u guys think its safe to assume that the first one is stepping down and i can ask the second one?
i know replacing one bm for another isn't very nice, but i don't feel as close to the first girl anymore. please don't yell at me guys.
btw- i can't have them both because i already have 7 girls in my bp.