Follicles good sized but scheduled for another ultrasound...

I went for my day 11 ultrasound today and saw that I have two mature follicles (24 mm and 15.5 mm). The tech said I would probably get a call later today telling me to take my trigger shot tonight and <a href="https://glowing.com/glow-fertility-program">IUI</a> Wednesday but when they called they said the doctor wants me to come in for another ultrasound and bloodwork Wednesday because they want them to grow a little bigger... I feel like 24 mm is perfect size, no? I’m nervous it’s going to be too big if they keep pushing back the <a href="https://glowing.com/glow-fertility-program">IUI</a>. Anyone experience this??? And have success??