Spending the night with grandma

How old was your child when you let them stay the night somewhere other than home? My mom has been asking to have my daughter stay the night at her house and now that she is no longer breast fed I really have no reason to say no. I’m a stay at home mom so a little break wouldn’t be so bad but then again I get anxiety just thinking about being away from her 😖 She’s 14 months btw.