Genesis 18:14 Is anything too hard for the Lord? At the appointed time I will return to you, according to the time of life, and Sarah shall have a son.
Although we may begin to accept that God can do anything, we do expect Him to do things according to our own timeframe; we expect Him to answer prayers when we want and to do what we want!
God has given us enough examples in our history for us to realise that He answers according to what He knows is best and according to His times and not ours.
When the Lord said to Abraham that his wife would have a baby it was certainly not in their times because they thought they were both well past having children – but with God it is possible!