I was 41 when I became pregnant with my twin daughters. Thanks to acupuncture, yoga and a wise obstetrician who convinced me to renounce vegetarianism and gain 50 pounds, I successfully nurtured two babies through a nearly full-term, mostly blissful pregnancy.

My "advanced maternal age" -- prenatal checkup speak -- didn't faze me. I didn't feel old; I was healthy and in better shape than I had been in my 20s and 30s. Well-placed highlights in my brunette waves rendered my few silvery strands barely perceptible. And I was still able to read the Sunday newspaper without cheaters.

Once the girls were born, however, I began to realize why new motherhood might not be meant for the middle-aged. Sleep-deprived, moody and forgetful during those first grueling months of baby care, I didn't know if I was suffering from postpartum blues or the onset of perimenopause. Turns out it was both, exacerbated by the physiological feat of maintaining a milk supply sufficient to feed two hungry infants.

Years later, upon joining a preschooler mothers' group, the other moms seemed young and, indeed, were young: One had been born the year I graduated from high school. Another had never seen a rotary-dial telephone like the toy her son was holding. We had little in common besides our young children.

Friends in my age group were visiting college campuses while I was choosing a kindergarten. Most of my daughters' teachers have been young enough to be my children, which can make it difficult to interact with them as peers, especially when I don't agree with them. More than once I've caught myself scolding them along the lines of "What? Taking away recess when children can't sit still is like taking away food when they're hungry!"

Now, my daughters are on the cusp of adolescence and I'm making my way through menopause. Together, we're a simmering cauldron of hormones just waiting to boil over. According to them, I'm too old to have long hair or dance hip-hop; I tell them they're too young to watch PG-13 movies or call their parents "stupid." They want me to get a makeover, complete with 3-inch heels and hip-hugging pants. I want them to wear shoes with arch supports and cover their navels. They're embarrassed by the way I laugh, talk, chew and breathe. I'm embarrassed by the way they clam up around adults, forget their instruments on orchestra day and procrastinate.

Thankfully, they still appreciate stories about my childhood: watching, on black-and-white television, JFK's funeral and a man walk on the moon; hearing about hippies, draft-dodgers and bra-burners; praying for "our boys" to come home safely from Vietnam; learning life lessons from Archie Bunker, Mary Richards and John-Boy. My daughters find it hard to believe I grew up without fast food, cell phones, the Internet and being able to hold 1,000 songs in the palm of my hand. One thing about being an old mom: History lessons are taught in the first-person.

When the girls turned 1, we threw them a birthday party. Amidst the cupcakes and ice cream, another new mom, 10 years my junior, approached me and asked, "Do you want to have more children?" It seemed like an innocent question, so I answered, "Probably not. We were lucky to have two at once!"

The inquiry has persisted over the years, made by different people in different places under different contexts: "Do you want to have more?"

Now I understand what they were too polite to really ask: "Are you crazy enough, at your age, to do it again?" And now I answer this way: "I wish I could."

How, in your experience, does age affect one's experience of motherhood?