You took the mission. You are the leader. And as a leader, you know, only when you give freedom to others, give them responsibility and trust them, you will get the freedom to focus on the bigger goals.
More often than not, the leader either would keep himself fully occupied in the day to day tasks, keeping full control or will give freedom to everyone and will give up the control. Either way is okay depending on the personality type of the leader and how well the organisation structure is set.
Even after giving the control, the leader always should keep bird eyes view on the business and dive in as and when needed to motivate and guide the people.
This diving in should be done only when needed and should not be done because you are worried but should be done because you see there are gaps that need to be filled. Once your task of filling up the gaps is finished, set up the monitoring system, give the control back and get focused again on the larger goals.
A leader should always jump in, if it is in the betterment of the organisation.