Hun, babies are all so different! I was writing my own 'worried mum' post a few months ago about my DS.....my DS is 15 months and only started 'properly' crawling 5 weeks ago (he was commando crawling for aaaaaaages). He only sat up all by himself unassisted at 8 or 9 months, he isn't walking yet and only says mum, yum yum and makes a car noise. I used to be worried but now I'm chilled! I'm dreading when he starts walking as I know he'll be into EVERYTHING!! Don't worry hun, it's so hard not to compre especially when you have other children around to compare to!