When many next level leaders are promoted, they find themselves managing people who were previously their peers. This can be awkward in some cases, but when you approach it proactively, it doesn’t have to be.
Just because you’ve been promoted doesn’t mean that you’re superior to your former peers. They are still the talented individuals they were when you worked side by side. Their concern is likely that you will treat them differently, and may even fear that you will no longer treat them with respect.