Her first temper tantrum !!! 😞😭

So today my 15 month old daughter decided to throw her first temper tantrum. I honestly didn’t know how to handle it or what to do.... of all places she decided to do this at a full courthouse (getting a divorce) I felt like a shitty mom everyone looked at me I could feel all the judging going on. My baby girl has always been well behaved it was shocking to see her throw herself to the floor, crying and screaming till she was red in the face ! How am I supposed to handle this ? What am I supposed to do?