As the older sibling, you spent the early days of your childhood enjoying the power that you had over your younger siblings.
You enjoyed that power, and since you were the oldest, you assumed that you would always have it. Sure, your parents may have told you that your siblings could pass you up, but you didn't believe them. How could they possibly know how tall you would get?
Then suddenly, your sibling started inching up. You wanted to watch them like a hawk, because you knew that you were in danger of becoming "The Short One." At the same time, you couldn't possibly give them the satisfaction of knowing that you were afraid of their growth spurt. You, unfortunately, came to the conclusion that you couldn't be so subtle forever.
BAM! Your younger sibling was magically the same height as you. You tried to be calm, but everyone and their mother couldn't stop talking about how you were now the same height, how you looked like twins (even if you look nothing alike). In denial, you were willing to do just about anything to refuse acknowledging that fact.
And then... It happened... Your sibling inched past you, leaving you in the dust like a sad, pint-sized elf. You initially had hope that you would grow another inch or two, or that your sibling would stop growing, and you could remain the same height. Instead, you were filled with disappointment.
The years of waving your superiority over your sibling's heads (literally) were gone. Your sibling couldn't wait for revenge. Suddenly you were the one who was too short to reach things - even though that may have not been true. Every time they waltzed around, you were reminded of your new, short status. Deep down you knew that you had no right to pout. For a reason you really couldn't explain, it hurt to see your sibling's height advantage. There's also a good chance that you were physically in pain, as your sibling seized the moment to torture you in exchange for all the torment you caused in your early years.
The pain eased with time, and you accepted that you would forever have to stand in the shadow of your towering sibling. Being "The Short One" would have it's ups and downs, but you could sleep peacefully at night knowing that at least you wouldn't have to worry about banging your head on a door frame or hitting it on the roof of a car. You can mock your sibling for their height-related injuries.
