This thread comes up once a week on here now I think! 
No, I would never have a baby past 40. Each to their own, but there are more 'againsts' than 'fors' IMO. As I said the other day on a thread like this, whilst you feel like healthy, vibrant, chipper 40-something, and feel properly ready and fit to handle a baby, you have to remember you will feel a lot different at 52-54 than you do at 42-44.
Menopause is a killer. You're tired and weary a lot more, and crabby half the time, and have sod-all patience with anything. And more physical ailments will kick in. Do you really want a 10-12 year old tween when you're knocking the door of your 60s?! I certainly wouldn't. I love my DC with all my heart, but now at 50-ish, I am more than happy to have an empty nest now. Been there done that, no more, no way.
This is our time now, DH and I. I especially don't understand why anyone would want to bring another child into the fold at 40+ when they already have children (and the last one was often a decade or more ago.) Resist @PastryandCoffeeallday don't do it. You have a teen already. Don't start over again!
As I have said before, I see a lot of women here who claim they have had one or more babies, past 42-43 years of age. I don't see it in real life. At all. And I live in an upper middle class area with many professionals around me.
It's like on mumsnet, all women who claim to be professionals/on £100K a year etc claim they kept their surname on marriage. In real life, every woman I know changed it to their husband's. Even the highly paid, highly educated professionals. (And the ones who claim to be ardent feminists!)