It was late one Saturday evening when she finally got home after spending a day with her boyfriend. I heard the front door open and, as I normally would unless my mood dictated otherwise, readied myself to greet her excitedly.

But Kay (19) was in a foul mood. She had opted to gallivant with Nicolas (19) that day instead of clean her room. So when she got home after an activity-filled 12 hours to find that neither my father, mother nor I had cleaned her cluttered chamber, my warm greeting was met with a cold response.

Worsening her mood was when she discovered I had bought a pair of pants and shoes similar to hers – a sister no-no if ever there was one!

But as I lay in bed later that evening, I heard a soft knock on my door.

“Kim, are you going to sleep now?” she asked.

She sat on the edge of my bed for the hour that followed, filling me in on her day and eagerly enquiring about mine, copied clothing items long forgotten.

That’s what it means to have a sibling.

Kay is three years my junior, so the age gap is quite small. I’m grateful for this because it means she’s my forever best friend.

However, the small age gap doesn’t mean that I’ve somehow managed to escape the Older Child Curse.

So today, on National Siblings Day, I’ve decided to reflect on what it means to be the eldest sibling.

You’re the trial run. Your parents practise their child-rearing modus operandi – including the rules and discipline styles – on you. So by the time child No 2 arrives, they’ve sort of figured out what needs to be emphasised what’s trivial enough to let slide.

You’re also (unwillingly) the example. Naturally, I completed my school career, tertiary education and landed a job before Kay did, so she automatically follows my lead. I don’t often tell her this but knowing she looks to me as a role model keeps me on my toes.

You’re the spoiler. As the older sibling, how many times haven’t you vowed to splurge less on spoils for your younger brother or sister? But the truth is, there’s nothing quite like seeing the appreciation on their faces and hearing how you’re “the best sister in the world!”.

You’re an influencer. Forget Instagram. As an older sibling, you’re a direct influence on your little sis or bro. What Kay wears, her hairstyle, whether she’s overreacting in a specific situation – all of those she runs by me first.

Every sibling relationship is different. To me, my younger sister is like a practice run of what it feels like to be a mother. The concern, love and good wishes I have for her are what I’m pretty sure a mother’s heart carries for her children.

To me, having a sibling means she has my back no matter what. After walking away from an intense screaming match with my father, I’ll come back to hear she gave him an earful in my absence.

Your relationship with your brother or sister is an extra special one that needs to be cherished – they see you at your worst and still choose to love you.

On this National Sibling Day, what does being a sibling mean to you?