I do notes on my outline. They're very similar to what you've done here with the three days thing.

Two years ago I wrote a novel with the main character who was pregnant. I researched dates for when the pregnancy occurred, when it would have been noticeable to others within the world I created, when the baby would arrive, and I had a trusty pregnancy book to remind me of all those stages as she went through them.

It's not the same as having a chart to say "oh, she felt the baby move for the first time on x day" but it happened after most of the nausea went away and before another plot point (probably Christmas). But it worked to keep my details together and from letting things happen too fast, and as long as you feel it is working, it should be fine.