I've posted this before, but it is appropriate for this discussion.
When I turned 60, my sister (a psychiatric social worker) sent me a paper someone had done interviewing many people who had lived to be 100, asking them which time was the best in their lives. Their answer overwhelmingly was their 60's. The kids were grown, they were enjoying their grandchildren, they were more financially secure, and by and large they were still healthy enough to do the things they wanted to do. Earlier decades were always seen as more stressful, whether it was induced by their jobs, their kids, their aging parents, or their finances. It seems it took most people into their 60s to find peace and contentment in their lives.