YOUR PARENTS HAVE ALREADY MADE MOST OF THEIR MISTAKES. We still make mistakes, but by the time our second came along, baby care was second nature to us. I could mix a bottle of formula in the dark and make it perfect every time. While with our first, I needed lights on and complete silence, as I precisely measured water and formula. I also knew the power of taking a baby on a long walk to get them to sleep.
EVERYONE LETS YOU WIN. My little guy always likes to race. He wants to win so bad. And usually we let him win so he doesn't freak out. Our oldest doesn't care who gets up the stairs first. But it's life and death for the little one. Honestly I use racing as a way to get him to move quicker.
STEP UP ON EVERYONE IN NURSERY SCHOOL. My daughter is two years older than my son, so he has been hearing about letters and shapes and colors from before he understood what he was hearing. He knew the alphabet and his numbers when he walked into nursery last year. He got the concept of homework, it was just something kids in school do.
GET TO PLAY WITH THE BIG KIDS. Since my son was very small he played with kids two years older (or more) than him. Tagging along at play dates or letting his big sister find new kids at the park. It was that way until he made his own friends.
YOU GET TO SEE WHAT A KID IS SUPPOSED TO SOUND LIKE. My daughter had speech delay, but for years she basically only heard adults speak. But the little guy had the benefit of having a talking and walking little kid in his house. He got to hear her talk and he sat around us when my daughter did her speech therapy exercises. So he was able to soak in all that knowledge.
PEOPLE KNOW WHO YOU ARE. When we visited with my sons pre-k teacher we noticed his name was first on the "helper" list. Is it because he's a good boy? A nice boy? Or is it because he's been going into that class room since he was two years old. I don't know. But he is following a very nice and sweet sibling in our very small very familiar school, so that is an advantage for him.
So being a second sibling is not as bad as second kids always says it is.
The author is a firstborn son, who has a nearly forty year old younger brother who is still trying to catch up.