We’ve been there. We started off slow and moved her up halfway through the year. We were pretty flexible too. I know a lot of parents who really stressed over not being able to have their child in a place for half a day. They said he/she got used to it, but the first few weeks were quite an adjustment.
When we bumped our DD up to more days a week, but half day she was happy but pretty cranky because of the change in her schedule.
Hope that’s helpful,
E