Is my lo behind?

Julie
I'm seeing posts about our 4 and a half and almost 5 month olds setting up unassisted, rolling already, crawling even! Should I be worried that mine isn't doing any of these things yet?? She has learned how to blow raspberries (fart noises for lack of better explanation) and has said "momma" quite a few times but nothing like the other posts. Just getting quite nervous. Anyone else the same level here???