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

Narrative

I was trying to take photos of a crypt at the cemetery from above.Once I took off; I saw a plane fly over; and I realized that I could be in a class B airspace. I landed the drone and took photos from the ground instead with a different camera. I was in the air for less than 10 minutes; and I only hovered above one spot; no more than 15 feet above the ground. When I got home; I checked and found that I was in a Class B airspace; less than .25 miles from the unrestricted airspace. I thought that I was far enough away from the airport that I wouldn't be in restricted airspace anymore; but I was mistaken. I only flew the drone 15 feet above the ground and landed it once I saw a plane fly overhead. I realize I could have gotten a LAANC approval; as well; but I didn't. Next time; I will be sure to check the airspace at my location instead of assuming I am safe. I will be especially cautious in airspace that is relatively close to airports and will ensure that I check if I need LAANC authorization before I takeoff anywhere.