I was struck by the section in Anne Morrow Lindbergh's Gift from the Sea where she talks about midlife--with its changes, emptying nest, closing of some avenues--as a time less of decline than of potential. The time we often call a crisis is one she likens to adolescence, another time of change and often turbulence. She speaks of midlife as a "second flowering" whose changes may be "signs of growth" rather than decline. We may grow into "a new stage in living when, having shed many of the physical struggles, the worldly ambitions, the material encumbrances ... one might be free to fulfill the neglected side of one's self. One might be free for growth of mind, heart, and talent, free at last for spiritual growth ..."
I certainly have felt this shedding and these changes as a time of preparation, of making room for some new phase. L.M. Montgomery's Anne of Green Gables always spoke of a "bend in the road" when faced with uncertainty in the future (as opposed to those times when our next steps lie straight ahead, clearly foreseeable). I identify with that, too: midlife can bring a bend in the road, and it's possible to approach it with enthusiasm as well as trepidation.