Why such a delay with the biometrics appointment?

My wife is from Eastern Europe and we sent off the I-751 to remove conditions before we apply for citizenship. We are waiting for them to send us the appointment date for her biometrics and it has been over 30 days since they received (and confirmed receipt) of all of our information, so we called to see if everything was ok and they said for us to wait another 45 days. All of our friends said that they received the appointment date within two weeks of immigration receiving their application. Anyone have this happen to them? What is going on - why do we have to wait so long? Do you think everything is ok? I am sure everyone that has gone through this knows how nerve wracking this is. Any insight would be greatly appreciated.