General questions

Alright ladies, I'm getting married in a month and have what will probably be a very silly question haha. How possible is it to get pregnant the last day of your period? I'll be on the last day of mine on the day I get married, but neither one of us has ever had sex before..and if possible would like to experience it for the first time without a condom. But I definitely don't want any honeymoon babies. If anyone has answers, please let me know! Thank you in advance! Sorry for the tmi haha.