There are two types of people in this world: those who have a dog and those who include their dog in their Christmas card picture. We are proud members of the second group.

We didn't just consider Reagan to be "good practice" for kids when we got her—she was our first child. As soon as we were out of the puppy potty-training phase, she started sleeping on our bed. We planned weekend mornings around her dog park trips and happy hour locations based on dog-friendly patios. We worried about leaving her home alone too long and, like most new parents, probably took her to the vet more often than needed.

We even navigated our relationship differences and discipline ideas with her. There were days when my husband and I got upset at each other if he was too tough or I was too soft. What kind of discipline is warranted, for example, when she chews up my leopard flats? Is it really that big of a deal if she eats some table scraps every once in a while? At the time, these were major issues (oh, how our worries have changed!).

I worked from home when I was pregnant, which meant that Reagan and I were inseparable. I'd joke that I had the best co-worker in the world. Still, I knew that our little family life was about to change and she was in for a shock. Once our son was born, she was clearly apprehensive about it all. She has always been the sweetest dog, and she was just as gentle as we thought she’d be with a baby—from a distance. During those first few months together, she only reacted to him when he’d sneeze or scream. Who was this tiny human and why was he so loud?

Now, that baby is a crazy toddler who calls Reagan "Ruff" and regularly invades her personal space and suffocates her with hugs. He talks to her, kisses her goodnight and says "bye Ruff" every time we leave the house. She checks in on him during bath time and is there when he's up crying at midnight due to double ear infections. She has overcome that initial distance and is fully comfortable licking him right on the face and, most importantly, sharing food. My heart aches every time I see their sweet interactions. To each other, they’re siblings; both integral parts of our family.

My husband and I laugh as we chase our toddler around, thinking about our “puppy parent” stress years ago. But we also recognize all that Reagan has taught us – and all that she’s currently teaching our son. She turned our selfish, young adult lives upside down with responsibility (in the best way possible!). It’s one thing to grow up with dogs and quite another to have your own; to feel the full weight of caring for someone who’s completely reliant on you.

A constant comfort for everyone in our house now, Reagan demonstrates unconditional love, entertains us endlessly and reminds us what matters. She didn’t hold it against me when her space shrunk to make room for another or my phone picture roll changed from all Reagan to all baby. Come to think of it, she’s the best model for forgiveness and selfless love I know. And we could all benefit from a little more of that in this world!