Is this normal procedure??

We have been licensed and home study approved since September 2011. Since then we have been in the top 5 families for a baby every month but have not been chosen as the selected family...until recently! We received a phone call from our social worker at the beginning of February and were told that we've been selected for a 4 month old baby boy!! BUT, we have to wait a month (and will be put on "hold" for any other babies)....the county has to rule out one more family that is not biological but is close to the biological family before we can proceed. You would think that the county wouldn't have told us until they settled all of that already, right? The court date is tomorrow and hopefully we will hear something within the next couple of days. Our social worker said that it is good that we haven't heard anything from the other family cause if they wanted to take the baby we would have heard of that already. SW also told us that once they rule out this other family the baby is low risk... Would love to hear if this is a normal situation or is it unusual that they would tell us and then make us wait and be put on hold for any other babies that may come into the system?? Thank you!