Your cervix is ajar....

How do you know when you are dilated? Is it like when the car door is left open? Will something in my body tell me my cervix is ajar? Maybe I will be like a turkey and my belly button will pop out. Just like the red turkey timer. I have been having contractions and cramping off and on all day. Maybe the baby knows that we had the car seats installed today. He might be getting ready.