When I adopted my baby, Belladonna, from HART of Maine in January 2013, she was just under a year old. She looked every bit the gangly teenager: long and lanky and tipping the scales at a diminutive 7.5 pounds.

Part of her small size was the fact that she’d been diagnosed with diabetes as a kitten, and although she’d gone into remission while in HART’s care, she was still catching up a little bit in the weight department.

Bella also acted like a silly child-cat. My well-thought-out plan to leave her in a room of her own so Siouxsie and Thomas could get used to her was scuttled in about five minutes: She slipped between my legs when I opened the door and trotted out into the living room with her tail held high. I could almost hear her saying, "Hi! I’m a kitten!"

Thomas and Bella touched noses and that was it: They were completely smitten with each other and have been best buddies ever since. Siouxsie accepted her with a grumbling sigh, which sounded to me like, "Oh, I suppose …"

From that day forward, she had me smiling and laughing every day. Whether she was running up and down the cat tree like a monkey on crack, flinging her toys six feet in the air and chasing them down the hall all a-trill with meows and chirps, or doing ridiculous gymnastics on the cat condo, not a day went by without a tinge of joy that I’d lucked into having this amazing little cat in my life.

It seems to me she matured a little bit on our cross-country journey to our new home. Every day when we got in the car, she settled down and curled up in her carrier for the hours we spent on the road. She did give me a scare once, though, when she decided she was going to try to escape her carrier and nearly strangled herself in the process.

But once we landed in our new home, she was once again all kitten, all the time, now with a new and even cuter trick: the frog-leg pose. I’ve seen dogs do this, but I’ve never in my life seen a cat lie down with their rear legs splayed out behind them.

We lived in a very small apartment, so Bella’s moments of manic toy-chasing included mountain runs over my bed, the couch, the cat tree, the counters, and even over me more than once. She also got into the bad habit of chasing Siouxsie around the house.

"You be nice!" I’d snap at her. "Stop chasing your Siouxsie around. She’s an old lady and she deserves your respect!"

Every time I scolded her, she responded to me with a single flip of the tail and walked away with her nose in the air.

But then last week, I was sitting on the Strange White Chair in the bathroom, where Bella loves to visit with me, when she hopped onto my lap and lay down, purring and rubbing my hand.

Suddenly I noticed something had changed.

She was heavy. Not fat, but lean and solid.

Her energy was different: Instead of spastically writhing around or walking between my legs, she sat and looked me in the eyes, and if she could talk, I swear she would have been telling me, "I’m here. All the way here."

And at that moment, I realized my little kitten had become a grown-up cat.

What about you? When did it dawn on you that your little baby was all grown up? Share your stories in the comments.

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About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.