I would not worry. The normal range is 12 to 15 months and she is only 14 months corrected so since she is cruising and starting to stand on her own she will probably start actual walking anyday. Have you tried one of those walk behind toys they can be great for getting them interested. All of my kids would love them.
I used to work in the infant rooms alot when I was in daycare and I can understand about them being afraid she will get hurt by the bigger babies but you can still ask that they give her plenty of floor time just not necessarily in the same area or at the same time as the bigger infants. What are the ratios of teachers to babies there? Sometimes if it is high babies have to spend more time contained in exersaucers, bouncy seats, swings etc then is really good for their motor development.
