Part 107 UAS pilot reported flying in controlled airspace without authorization.

Narrative

I am a wedding videographer who was filming a wedding at the stadium on Day 0. I had checked the sectional chart prior to take off and my interpretation was that the stadium was outside of the class C airspace for ZZZ. So I proceeded as normal and began my flight with my UAS. The app also did not inform me that I was within in sort of controlled airspace and allowed me to take off as normal. I flew for approximately 8 minutes in and around the stadium; capturing video for the wedding couple. After I concluded my flight I was informed by the event staff that the police had been notified and they had came over to stop me for flying. I was then informed that I was not permitted to fly because of the helicopter pads nearby for the hospitals. After that; I later figured out that the stadium is also indeed right on the edge of the class C airspace for ZZZ. Going forward I now am totally aware of the airspace occupying the stadium and will no longer conduct any UAS operations without prior authorization.