Charlie could stay in a sitting position if we put him there around 5 1/2 months, but he couldn't get to a sitting position and stay there on his own until he was 7 months. He actually started crawling (army crawl) at 6 months before he sat up.

Olive is going to turn 6 months soon, and she just started rolling over so I know she's a ways from sitting up. But sitting up is such a fun milestone, and it's easier to take pictures of them when they're sitting up!