Linea Nigra & Gender

Has anyone heard of the old wives tale about the Linea Nigra? If it goes from the bottom of your belly to belly button then you're having ab girl.. If it goes all the way up your belly you're having a boy? ... I'm so curious to find out the gender because everything is pointing to a girl. Moody, heart rate was always over 160, Linea Nigra stops at my belly button, vomit & nausea 😣 I've also had multiple dreams about boys .. Can anyone tell by my ultrasound? This was at 8w5d