Advanced baby?

Keri • "Happiness can be found even in the darkest of times ; if one only remembers to turn on the light"

My little guy is 6 months old. He has been crawling, pulling himself up on the couch and moving his feet to pull himself along and completely sitting up on his own. He’s also able to pull himself up and stand on his feet. Is this the usual age for this to happen?

According to this app the milestones he should be reaching in months from now he’s already achieved by 5-6.