Reporting to someone younger is hurting your ego. Get over that mindset. It is archaic. You may had team members who had more experience or better qualifications than you. The work output is what matters. The years of experience and qualifications has limited value in the job market after a few years. The same goes for credentials. When a song becomes a hit, we do not care how old the singer is and if the singer holds a degree in music. Employers are no different.