Period and iud

So they made my IUD appt for tomorrow because my period was supposed to start today. But it has yet to show up. Do I still go even though my period hasn’t came yet?They said it’s easier to insert when your on your period. I really don’t wanna have to miss Work again if they won’t insert it tomorrow. Idk

UPDATE: It went very well! The pain was like a normal period cramp. And now it’s just crampy. I would so recommend it to my friends. Thank y’all for the advice!