Can a girl have period before 15 days after taking...

What is our advice
According to world health organization WHO, there is what called emergency pills. Emergency pills are medication that are taken to prevent pregnancy after intercourse. Plan B pills contain leveonorgestrel and it prevent pregnancy with efficacy from 55%-98% if it is taken within 5 days after intercourse. In other words, if this medication was taken after 5 days there is a chance of pregnancy (chance does not mean that it is a must that it will be pregnancy)
What is other emergency pills
Ulipristal acetate 30mg
And this pills are effective up to 98% if are taken within 3 days from intercourse
How to make sure that the pills was effective in your case:
You have to wait until the next period date, if there is a period this mean that the pills was effectvie. If the period delayed you need to do blood pregnancy test to make sure there is no pregancy
Again, if you had the intercourse before within 3 days use ulipristal acetate 30mg once. If you had intercourse before 5 days or less use plan B once