I guess it depends on how she gets on with your Mum. I left Ryan for the first time at 9 months with my Mum and Dad (granted it was at home, they stayed there) but Ryan was an angel for them and actually slept in for them which he never did at that age for me
I also made sure my parents were consistent with my schedule so everything was kept the same for Ryan.
It is very stressful I think for us Mums to leave our kids the first time.
She may cry when you leave but so long as Mum can distract her I bet she will be fine after a few minutes.
HTH!