It's important for you to keep up with the process of time in your story. All things happen in a sequence and keeping track of that helps so much in the long run. You may change chapters' order or their scenes, but in doing so aren't you also changing the sequence of the story.
You have a lovely couple, the have a baby, the marry, the fall in love, they meet, they get engaged. Wait. What? Is that right? Maybe half of it. I can see having a baby, falling in love, then marriage. But they first have to meet. Unless it was a one-night event and they didn't even meet, just did the deed and got pregnant. (It happens.) No, it doesn't.
By keeping a track of the timeline, you help yourself with the process of the story. If you change a chapter or something in between, you can refer to your timeline and realize that you can't change the order of the chapter and if you do, you might need to make some great changes to it, in order to make it work.