Myth or fact?gender prediction

So,my friend told me that, the first date of your last period before pregnant can predict your baby gender. If it is odd,your baby will be boy. If it is even, your baby will be girl.. i am 6w now..and my first date of my last period is 27..so it will be boy..hahaha..i just wondering is it true or just coincidence?i will not know until i find the gender... so anybody here remember your first date of your period and is it true about your baby gender???