Y'know you can always start her soon-ish, see how she goes and make a decision then? If it's not working no drama you just take her out again. And just because you have her booked in the whole day you can always drop her off late or pick up early so it's not such a full day for her.

Leaving a first born in child care for the first time is stressful and hard no matter what! I found that my centre were so lovely and open and happy for me to hang around the first few times and gradually leave him longer etc and they took such an interest in him and got to know him and me quite quickly and now I trust them totally. I know he's having a great time and that helps a lot. Once you know she's having fun it does change how you feel about it.