Being an "Older Mum"

Funny, there are a few great posts around at the moment about being an older mother. (By that I mean birthing at a later age rather than just being a mother who's getting older.)
Scary Mommy is writing about being listed as an A.M.A in her post, and Kate Kerrigan is writing about having her second at 45 over at the Brit Mums blog.
Regular readers will know that my teens were 10 and 7 when the "surprise" Little Guy came along. It wasn't in the "big plan" but then, as my mother said at the time "More fool you for thinking you were in charge of things". (She was actually very supportive at the time, and that statement though true, doesn't do her justice.) At one point I had been very undecided about whether to have a third child, but at about 37 figured that I'd better not, as I "didn't want a toddler at 40". Ha! Famous last words. Why not just have a baby in your 40's then?
To be honest, apart from the fact that I'm still doing the brushing-teeth-and-bedtime routine when most of my friends have a new-found freedom that comes with teens who can drive and don't want you around much, it's all good. Yes, I wish he wasn't so much younger than his peers; I feel terrible that in two years both siblings will be gone and he'll be stuck with his geriatric parents. I worry that I won't be around to see his children; the list goes on.

But on the other hand, who would I have to do this with?