How many months old was your baby when they sat up? I think the norm is between 4-6 months which is a big range.
My LO is only 4.5 months old, but she really doesn't like sitting up even on our laps. She throws herself backwards or wants to stand up. As soon as we lay her down or stand her up shes fine. This is now impacting starting solids because she gets frustrated sitting in the high chair. Also, bath time is quite the chore because she obviously can't lay down in the tub and she is horrible at sitting.
Did it take a lot of practice to help baby learn to sit? I am so afraid she won't meet the milestone because she won't practice with us. It also doesn't help that I don't know how much practice she gets sitting up at daycare.