So why this blog?

I've been seeing in advertising lately that they are saying '40 is the new 20' and I thought, 'ok, that sounds intersting. Seeing as I turned 40 last summer, I thought I'd start writing about what the new 20 feels like from this 40 year old's view.
To give you some background, I think I'm a pretty average 40 year old. I've been married twice (second one stuck, we'll have our 10 year anniversary this summer) I have 3 kids, 1 step kid, a dog, a house, a mortgage, a mini-van, and a pretty good job. I have a circle of great friends, some I've known since high school. I enjoy working in the garden, traveling, shooting photography, reading a good book, and sitting at the ocean feeling the breeze and watching the moonlight dance off the waves.
I've faced my share of tough times - lost jobs, lost family members, lost loves - and grown stronger in the face of adversity.
So what makes 40 the new 20? Is it that we are living longer? Are we not growing up till later? Are we more responsible? Are we taking better care of ourselves?
I look in the mirror and I don't think I quite look 40. I look like I'm in my 30s I think. Maybe it's vanity saying that. Does it really matter? Did my Mom look older to me because she looked older or because I was so young?
We'll ponder this more in the coming weeks.....for now, back to work!