My baby will be home next week

and he is 5 months old. I have a 5 year old that I have the option to keep home with the baby and I or I could send her to Kindergarten (which she could miss for a few weeks since this is her second year of Kindergarten..she has a late birthday). Anyway, I worry about attachment/bonding with the baby, but also helping my 5 year old feel good, secure, and not "replaced" by the baby. Any suggestions...send her to school or keep her home?