This morning I was approaching a roundabout. There were three lanes - two with queued traffic and my lane was clear. Just before the roundabout there's a traffic light controlled pedestrian crossing, the light was green. As I approached at about 25 mph a pushchair appeared with 3 kids piled in/on from between the lanes of traffic and I had to slam my brakes on as their mum was texting and hadn't even noticed me. She glared at me and carried on. I'm heavily pregnant so emergency stops are not ideal.
I saw her again on the way back to town and again she was crossing between traffic on a busy road. I then saw her in town while walking with dd and she said I should be more careful because I nearly hit her kids and they were terrified, in a really arsey and aggressive way. I said I'm sorry they were scared but perhaps if their mum would stop pushing them out in front of traffic/cars these things wouldn't happen. She said she'll 'report me for driving dangerously' 
AIBU to think I didn't do anything wrong and to have argued my case?