My grandmothers had a 24-year age gap. The difference in our relationships taught me youth and health aren't the same.

• Jessica Knurick was close with her 70-year-old grandmother.
• Her 46-year-old grandma was stern and less involved with the grandkids.

This as-told-to essay is based on a conversation with astrophotographer Jessica Knurick. It has been edited for length and clarity.

My Grandma Anne, my dad's mom, was 70 years old when I was born. My Grandma Marie, my mom's mom, was 46. When people hear that, they assume that Marie, being young and lively, was much more involved. That couldn't be further from the truth: I was incredibly close with Anne, while my relationship with Marie never felt intimate.

These days there's a lot of debate over the merits of being an older mom or a younger mom. By extension, people think about whether older grandparents will be around through their grandkids' lives, or whether younger grandparents will play a more active role.

I've learned that whether it's parenting or grandparenting, age really is just a number.

My older grandma was energetic and warm

Anne gave birth to my dad when she was 44. She'd had her first child 17 years earlier, and everyone knew my dad was an accident — or, to use the more polite term, a "surprise."

Despite being an older mom and older grandma, Anne was always energetic and full of life. She was a constant for me throughout my childhood and into my young adult years. As a kid, I loved going to her house for sleepovers or when she'd pick me up for an outing.

We would play checkers and just talk, or eat gummy bears. She was a gifted storyteller and I loved hearing everything that had changed during her lifetime. It seemed amazing to me that she was born in 1917.

My young grandma was still parenting and working

My maternal grandma, Marie, was just 46 when I was born. Interestingly, her mom was the exact age of my older grandma, Anne. One of my uncles had just turned 20, and Marie was still in the later stages of parenting. She had a full-time job, and it just felt like she had less time and attention to give to her grandkids.

I saw Marie often. She only lived about a mile away and my mom would bring us over to visit often. But the closeness was never there. She was closed off and stern, so I remember being a bit afraid of her as a kid.

My older grandma took care of herself, but my younger grandma didn't

One of the biggest differences between my grandmas is how they took care of themselves. Anne was super active. I don't mean that she went to the gym, but she was always out and about. I often tried to call her and got the answering machine because she was out walking, going to church functions, or visiting friends. She taught me how to take care of myself, from applying face creams to eating nutritiously, and she also inspired my decision to become a registered dietician.

Marie, on the other hand, was always either at work or at home. There was no community around her days. She ate unhealthy foods and smoked for her whole life, even after developing lung issues.

Despite their 24-year age difference, my grandmas died quite close together. Anne was 97, but Marie was only in her 70s.

I've learned that good grandparenting isn't related to age

As a dietician, I've focused my work on caring for pregnant and postpartum people. I see a lot of debate about whether it's better to be an older or younger mom. I shared the story about my grandmas in response to some of that debate.

Anne and Marie show that age isn't all that matters when it comes to nurturing loving relationships with our kids and grandkids. We need to take care of ourselves so we have the energy to match theirs. We need to be open and loving, and make them feel safe. That can happen at any age.