From an article on Americanbaby.com called "Surprising Mommy Milestones," by Julie Tilsner.
You know you're truly a mother when your diaper bag replaces your purse.
My first diaper bag was plastic and pastel green. It had little duckies on it. Pregnant with my first child, I thanked my mom graciously but vowed never to be seen in public with it. At the time, I carried everything I needed for life -- car keys, credit cards, bottle of water, and miscellaneous trash and receipts -- in a clever little purse. When my mom left, I threw the diaper bag in the closet.
Then I had my baby. Soon thereafter, I discovered that diapers, wipes, the changing mat, spit-up cloths, two changes of clothes, extra blanket, extra socks, extra hat, infant Tylenol, two bottles of milk, a hand pump, two clean pacifiers, the camera (just in case), my keys, my wallet, an emergency $20, various snacks, a liter of water, my cell phone, and a religious medallion (for luck) would not all fit into my cute little purse.
So I dug out the diaper bag and reevaluated its merits. It was waterproof! It was expandable! It had a separate compartment for poopy diapers! My little purse came up short in every category. In that instant I made the transition. I was a mom, darn it. I had to be ready for every possibility. I shouldered my diaper bag with pride from then on.
Until I potty trained my second kid, now 3, that is. I have a cute bag once again, but the contents -- much like my body and natural hair color -- will never be the same. Items found in my purse recently include a pair of vampire fangs, a toy car, a rubber spider, a Hello Kitty pen, three Little Mermaid Band-Aids, an unfinished candy ring wrapped in a napkin, and a bag of crushed graham crackers. I guess you can't go home again.