IUI #1 - follicle size question

Bea
After TTC for nearly two years and undergoing 6 months of tests at a fertility clinic, we began our first <a href="https://glowing.com/glow-fertility-program">IUI</a> cycle on June 5. 
I took 5mg Femara days 3-7 and went for my day 12 ultrasound today. Right side shows 3 follies, one being 20mm. Left side shows again 3 follies, one being 17mm. 
I am set to trigger tomorrow CD13 at 11PM and <a href="https://glowing.com/glow-fertility-program">IUI</a> is scheduled for early Monday, CD15. 
I am worried that I am triggering too late? Does anyone have any opinions regarding this?? Thanks!