I work Fridays and Saturdays. I used to work every Saturday and Sunday, and dh looked after dd but we had very little family time, so I swapped, and Mil offered to have dd on a Friday. All good, except mil is a very nervous driver and lives 30 miles away, so I have to leave by 6.30, then drive back to work, which is 10 mins from my house, then back to collect dd. We usually get home around 7, dd is starving, it's a nightmare.
Dd started playschool every morning this week, she is 3, and used to attend two mornings per week. Her best friends gran (her parents are deceased) has offered to collect dd from school every Friday and keep her til I finish. In return I will have her dd on a Monday so she can go to a club associated with her hobby.
She lives in the next road, I have known her since the girls were 6 months old and trust her completely.
Mil has gone mental. 
She feels used, thinks I am being selfish and putting pressure on her to drive on the motorway, and am exposing dd to unhealthy living arrangements. (Apparently being bought up by dgp's is unnatural, and the woman's husband could be a paedophile)
So frustrated. This new arrangement would be so much easier, and mil is forever complaining that she is spending her retirement babysitting. (She has sils dd 2 days a week too)
Aibu to stick to my guns?