Is it okay to start Nuvaring this late?

I started my period yesterday on Wednesday. I was going to get birth control today but it was closed earlier than I thought. I work early tomorrow so I don’t have time to get it before it closes. It’ll be open Monday and by then it’ll be 5 days after my period

I hear that you can start Nuvaring the day of your period or on the 5th day of your period but not a day later…

Problem is, my period only lasts 4 days long…not 5. Is it okay to insert it on Monday still?

Of course I’ll be calling them tomorrow to be sure, but I just feel like I need an answer now