When is the ideal week to have braxton hicks or contraction?

Hi Mummies, first time mama here. When is the ideal week to have those of above? Mine is 31 weeks, I THINK , isn't it too early for this? I'm not sure if im experiencing those, but damn it hurts especially on my lower belly. And also I'm having pressure pain on the area where I pee when I walk a bit too fast. I thought i need to pee but every time i pee, little pee came out. Do Mummies really give birth early and not on their EDD? #nervoushanyaallahygtahu