First time sex

Em

I'm getting married on Saturday and it will be both of our first times to have sex. I got the paragard in February and since then my periods have been very unpredictable. So my two questions are:

1. How are the strings of the IUD and sex?

2. How long until my periods return to normal?

I have terrible luck so I wouldn't be surprised if Aunt flo did show up this weekend. Any wives tale remedies to delay her?