天上掉餡餅了。 Your mananger effectively gave you a team to manage which is rare nowadays in corporate America. I believe the standard routine is to open a req and invite all those who're interested to fight for it. You must have impressed your manager enough to earn this. I would appreciate the trust from management and try my best.
When I made my transition, I kept reminding myself NOT be the person with best technical skill in the team. Manager is to manage which means trust your people. Your company don't need you to do the technical work.