Quick question for ladies that are 10 weeks pregnant with their first child

I am ten weeks and two days pregnant and I'm already starting to notice a slight dark line down my stomach. I knew it was going to happen, but I wasn't expecting it to show up this early. It's not very easy to see for my husband, but I can see it clear as day as it is my body. Anyone else in my shoes? This is my first child and I already feel huge.