I need some insight

Which ones? I recently found a really cool, completely free milestone app by the cdc that I'm using to keep track

My first did everything pretty early and fast. Sitting by 4.5 mo, crawling and pulling herself up between 5-6, standing by 7, walking by 9. My current baby boy is a little different. Rolling around 2.5 months, just started crawling at 5 months and can sit by himself as long as he doesn’t turn or get excited and throw himself back lol