FataliePorkman this is really horrible.
i cannot believe for a second anyone is suggesting you or your dd are at fault. That is crazy!
Please pick up the phone and ask your 'friend' what her text means. Get her to use her own words to confirm whether your dd is invited or not to the wedding.
If she has the audacity to say that your dd is not invited anymore then decide what to do.
I would say (and I am rarely the one to make a big gesture) "Very strange that you want to uninvite my daughter. I was not even aware that people could do that.
I've spent lots of money on XYZ to be there for you on your big day and you know there is not one to look after my dd so you must realise that this means I cannot now come to your wedding and be your bridesmaid. That is a real shame. Please see whether you can re-invite my dd so that this can be resolved otherwise you will need to look for another bridesmaid."
It's kind of your mum to offer to look after your dd but it does not seem fair for her to miss out. This 'friend' is putting you and your dd, and your mum, in a horrible situation over what, the cost of a child's meal!
Of course you should not need to persuade a child to be a flower girl! What rubbish. There is no way my dd would be able to do this. I remember massive efforts to get her into a nice outfit for a wedding at a similar age. (We failed!)
Equating being a bridesmaid with going to school, what is going on!
I have tried to push my kids into things in the past. There is always the worry they will say loudly at a very inopportune moment "And I don't like you and I never wanted to be here anyway!" Quite loudly.
This is not about you, or your dd, it is this 'friend' who has chosen to prioritize a distant relative over your dd, and therefore by extension, over you.
Totally agree with Itsout "Personally I wouldn't care about a friendship with someone who would be shirty with me if I didn't force my child to be a bridesmaid for her."