We must move from that point where we seek to understand everything that God wants us to do before believing what He has said that he would do. It is important for us to understand that He alone can see the end from the beginning and we cannot so it will not make any sense even if he told us how everything would play out from the beginning to the end of what He wants us to be engaged it. Mary wanted to figure how those events were going to play out but at some point she just realized it was not possible for her to figure out how everything would play out especially realizing that it was not a man that was talking. When a man is talking and he is trying to tell you what will happen, you may want to argue with him because you do not want to be deceived and logic can be introduced into your conversations with men. When you get talking with God the game is a different thing entirely. Logic has no place in the conversation with God because more than half of the things he will tell you about your life and the things that you will experience will never be logical. They are things that will defy explanation so you cannot expect God to work by logic.
There are times things have not worked for us because we expect God to present logical reasons for what he told us he would do for us but I must also say that God does not owe us an explanation for what he wants to do for us. He only expects us to believe that he can do it and we just need to leave him to the strategy he will engage for whatever he is going to do! If we are ever going to succeed and rise in life, going by what the word of God said or what God told us directly, then we have to stop trying to figure everything out and just come to the understanding that God will always be God and will not fail to do what He said He will do.
As for me, if God said anything that sounds unbelievable about my job, family, academics, social life, spiritual life, future or any other thing, I will just take the simple step that Mary took and say, 'be it unto me according to your word!' I guess Mary also realized that she didn't create herself and was not the one making herself promises that cannot be kept. We are talking about the God who made you in the first place who is now making promises to you so all you need to say is, 'I don't know how I will get there but be it unto me according to your word.' I don't seem to be qualified to get this but be it unto me according to your word because you will not fail!