Mary's response to the angel was one of complete submission, which is rare in the Biblical record. She doesn't bargain, she doesn't take things into her own hands, she just submits and lets things happen to her, knowing that it won't be easy and that it will be a huge responsibility. She submits as a servant, relinquishing all rights to self.
This is as nearly perfect model of obedience, next to Christ, as we can find in the Bible. She was aware of some of the initial hardships--bearing the shame without being able to explain or defend herself before her village, being at the mercy of Joseph--then there was also the unknown. But she didn't ask to know how it would turn out or what was in it for her; she just submitted.
These get right to the point in my life. I have a hard time giving up that "right to self," I guess. I get resentful that following God can be so difficult, misunderstood, and under appreciated. It is hard for me to remember that Jesus said "If anyone wants to be my disciple, let him deny himself, take up his cross and follow me." This is what we consent to. We have to remember that the cross is hard, and few of us will ever have to bear a cross as difficult as Christ's--or Mary's, or those of the early martyrs (or contemporary martyrs).