My babies not

I see so many post about getting teeth,crawling, sitting up,standing, eating, etc. My son will be 7 months in 2 days. He just now is starting to eat baby food. He would gag at everything except real banana in mesh feeder. He will stand if I hold his hands. He's not sitting up on his own without support. He's not crawling but today figured out how to get on hands and knees. He still doesn't have any teeth. Is my son the only one not doing all these things? I see all these post and just makes me feel like my baby is behind or I'm not doing something right or not doing something enough.