help leaving your bub for nan to look after.

I book a hair appointment a week ago and told my MIL who then said she could come with me and look after my chase (baby) or I could leave chase at her house with a bottle. anyway my appointments is this Tuesday and told she said to me leave chase with her and a bottle while i go to the appointment . I dunno if I ready to leave him that long. it going to be 2 to 3 hrs while I'm away. I talk to my partner about it and ask him would she get upset if I ask her to come with me as I'm not ready and he turn to me and said yes she will be and to leave chase with her he be fine. . I know chase fine it me not ready to leave chase. He is only 10weeks he always feed by the breast. He only ever had one bottle of 50ml and prob drink 10 to 20ml in 15min and then I top him up. I just wish I never told her and take chase with me.