Is it normal to miss period after iud insertion

So I got my iud in on the 7th. I was supposed to get my period that day but I never did. I bled for 4 hours and then it turned brown then stopped. I've had very irregular periods as well from October-December from being off of my previous bc and I bled basically every other week up until now. So the app may not have been right either. But is it normal to not have or skip your period if you get the IUD in when you're supposed to get it?