It is amazing to watch children grow and change. They all do it at their own pace. Benchmarks are somewhat useful to know what to expect, but every child does it at his or her own pace. I suppose there are somethings that you can encourage or "train" your child about but from what I have seen there are just somethings that they can't do it, don't show interest, are unwilling to try....and then suddenly the interest is there and the ability follows...often very quickly.
I really think that the ages they put on toys are a bit misleading. There are toys that might be safe for younger children, but (at least so far with my boys) they were not able to really play with the toy for a long time. We have had a puzzle since we were about 1 year old, but the boys didn't show much interest in it (they mainly used the pieces...which had handles...as instruments). Then suddenly when I was unpacking toys at our new house I saw Doug play with one of those shape sorting toys. He was pretty accurate and did it by himself, whereas before he could only do it with a lot of coaching. He then proceeded to floor me at my sister's house because he did a puzzle with 100% accuracy and no hesitations.
I know, also, that playing with older children over the holidays has forever changed Doug & Andy's play patterns. I will be interested to see as we get back to our normal routines what they still do after their exposure to both their cousins and now children of family friends at Nana and Pop's house.
Jo, I think, is about 1 to 2 weeks ahead of where Andy was with physical development. Andy always was my "gross motor" boy. He crawled, walked, etc. almost a full month before Doug did. Well Jo doesn't always choose to crawl still, but she can, and she is definitely able to sit up from a tummy position. She has started pulling up to stand up. She's not cruising along yet, but I think it can't be far behind. She just wants to keep up with her older brothers.
I was actually grateful when I had twins right off the bat, that they didn't have older siblings to try and keep up with. I am reminded, however, how important it is to have that peer group or role model to motivate them to take the next step. I am also thankful that my children are still young enough that most of the time I can make it a peer group of my choice because I do want my children to be able to navigate their own way in this crazy world.
I am reminded that having children is like ripping your heart out of your body and letting it walk around. At least the process of giving them more freedom to roam is gradual...