Dear Abby: Am I a jerk for setting limits on babysitting my granddaughter?

DEAR ABBY: Our adult daughter, “Amanda,” and our 3-year-old granddaughter, “Lucy,” live with us. I watch Lucy while Amanda works. Her commute to work is about 20 minutes. We live in a suburb of a big city, so once in a while traffic causes a delay, but not on most days. Amanda wants to leave for work an hour and a half before she has to be there because she is anxious about getting to work on time. I think leaving 45 minutes before she has to be there is reasonable. Am I being a jerk if I tell her I’m unwilling to take responsibility for Lucy until 45 minutes before Amanda has to be at work? I’m not trying to be insensitive to my daughter’s anxiety, but I have many responsibilities of my own, and my time is valuable. — BUSY MOM, TOO, IN KENTUCKY