This is going to one very steep learning curve for both. Exciting at times; and I'm sure a little nervy too. When I was flying air-taxis & night freight single crew I had a steep learning curve, also. Exciting and sometimes scary. CRM was a conversation with yourself. I had some 2 crew biz jet & twin prop time to fall back on in my decision making. After 6 years of that I had 7 years of airline flying before a pax jet command. That was after excellent training and excellent varied line flying with very competent captains. Years of basic flying, both GA & airline, before the modern new computer game stuff. The 1st year of command was exciting, but rarely nerve racking. The apprenticeship had been comprehensive. Flying was not the problem, you could or you couldn't. Simple. The decision making, both to be reactive and solve problems and also to be proactive and avoid them; that was the biggest difference between LHS & RHS. That takes time and exposure and good demonstrations of what to do and when. The pax climb aboard with total faith that the captain will 'save the day', as does the crew. Solid leadership. Most problems that need captain's intervention & judgement happen on the ground. There are no QRH's for what to do when you have 180 angry pax up your backside. They need strong authority to calm down; preferably strong leadership to keep them calm in the first place. Handling agents are no help. There are no station managers in LoCo's or charters. It's captain's call.
This is not a comment about individuals. I admit it is a generalism, but IMHO if you apply TEM and risk management to captain's experience of a pax commercial jet operating into 'out of the way airfields' I wonder if 3000hrs and <30years old would pass the assessment.
In 1988 I had a discussion with an HR dept of an EU major airline about captain's age. They had B732 captains of 28. Their answer to age was "the captain flies the a/c into only major EU airfields. Any problems outside the a/c will be solved by the station manager. Only flying skills with crew & pax management was required."
It will be a very circular debate with many varied opinions; no right or wrong.