Most of mine sat around six months,except Matilda and Merlin.Matilda was about 9/10 months to sit.We're still waiting for Merlin,at nearly nine months.My earliest walking was Erin,at ten months.Harry was18 months,Matilda was 17 months.Harry bumshuffled at 11 months and only crawled long after he could walk.The others all crawled aroungd 8/9 months.Matilda was n't crawling till 10 months cos she roll.Erin was crawling at 5 months though,long before the others,and feeding herself with a spoon at 9 months.
Mine all talked early,they've learnt their colours and shapes early.Harry was reading numbers by 2.Whirly could read her alphabet at just over 2,so they were all doing other things.
I think each child is an individual and they all do different things in a different order at whatever age they're ready.Merlin only learnt to roll over a couple of weeks ago.He's not crawling yet,he barely sits for more that a moment and is totally clueless about feeding himself.I'm sure he'll do it all in his own time
Walking at 6 months though is very early,you just wouldn't be expecting it.It was the climbing that followed with Erin that was the biggest worry,cos at that age they just have no idea of danger.