missin the egg with iui?

PkH
Today my follicle measured 21mm! I have symptoms of being fertile. They scheduled me to give trigger shot tonight and do <a href="https://glowing.com/glow-fertility-program">iui</a> Monday! Anyone have experience with <a href="https://glowing.com/glow-fertility-program">iui</a>? I'm nervous that I'll ovulate before then! Anyone missed ovulation?