Can you ovulate before trigger on Follistim cycle?

Going in for 3rd <a href="">IUI</a> on Tuesday!

We have been doing Follistim and have to do trigger shot on day 14 and <a href="">iui</a> day 16. <a href="">iui</a> was originally set for monday but got pushed back because doc wanted my 2 eggs a little more mature.

When i look at when i would normally ovulate on my <a href="">period tracker</a> app without meds, it shows tomorrow (sunday) is when i would ovulate.

Does Follistim push back ovulation? Will triggering tomorrow night(sunday) be to late for Tuesday <a href="">IUI</a>?

I just had U/S today so im guessing the doctor would have been able to see when i was about to ovulate? Has anyone done <a href="">IUI</a> day 16 before on Follistim cycle?