Cultural Offering's excellent post on the flaws of leaders sparks a lot of reflection.
I've studied world leaders for years and have concluded that the person's flaws almost always emerge, but they are less likely to cause serious damage if the leader is seasoned enough to control and compensate for them. There are exceptions. Richard Nixon was probably far more effective as a president in 1969 than he would have been in 1961, but extreme defensiveness eventually brought down that highly capable man. Time had not removed his inner demons.
Winston Churchill was certainly a far better prime minister than he would have been had he gotten the office while a young man. [He learned a great deal from the Gallipoli disaster.] It can be argued that Charles de Gaulle was a much more astute leader in 1958 than he was during and immediately after the Second World War.
Experience matters. We see its value time after time in our own lives and yet often lose sight of that when choosing leaders. Are you more capable now than you were ten or twenty years ago? Formal education can help, but there is an intangible education that can only come with age. This does not mean that all older people are wiser. It means the ones who have been alert and engaged and humble enough to learn from their mistakes gain an insight that the less experienced person lacks.
The expression "rookie mistakes" comes from the real world. All large organizations need and can benefit from the passion and fresh ideas of rookies, but don't pick one as your leader. Give that person some time to mature.