Commuting from Dunstinbourne Abbots to Gloucester

We're moving to the area and found a house in a village just outside of Cirencester, in Dunstinbourne Abbots. Meanwhile we had planned to send our daughter (4) to King's School in Gloucester. I'm realizing now that making that drive twice a day might be quite a lot. Can anyone tell me what a realistic commute time is between these two places? How is traffic along the A417 during the morning and late afternoon? We won't be able to visit for another month or so.