I guess its a bit of both really. I think it can be tough following on an older sibling especially if they are known for something or the other - like the star athlete's little sister that is just expected to win although it might not be her thing at all. It really has to be tough following a top academic achiever if you are just the average Jo Soap. Luckily I think in our family we may just bypass these issue.
However in some cases having older siblings certainly helps - they pave the road, show the courage and in some cases help their younger brothers and sisters. Although I am of the opinion that Mr C taught himself to read in grade R both he and A maintains that she had something to do with it. Whatever the case, last week he showed us not only his own guts, but that having an older sibling certainly helps.
When we get to gym on a Tuesday night the aquarobics class is still in progress in the small learning pool. Typically the boys will wait for the class to finish and the play in the small pool until their lessons and A do a few practice lengths before she plays a bit before her lesson. Last week Mr C tapped me on the arm (as he does) and said, "Do you think I can swim there?" showing the 25 meter pool. I said that he certainly could if he swam but no playing as people were doing their lengths. He got in and started with breaststroke following his sister and before long he was at the other end with a huge grin on his face and a high five from her. He turned around and did another back behind her to get a huge high 5 and congratulations from me. Boy, was I so delighted with this little man. He did another 6 lengths and then went on to his lesson. Following the example. I know a lot of kids his age swim these lengths regularly but for him it was a self motivated first.
BTW it's the second time in so many weeks that he has surprised his mom - at a bootcamp party he was the only boy of his age that managed the balance beam (a round pole) over the river without any help and while being harassed by the bootcamp instructor. He tried 3 times and succeeded on the 3rd try - quite amazing balancing skills. He thoroughly enjoyed the whole experience, the mud, the water , the toughness and skills. It seems my quiet little softly spoken soul has a lot more I still need to discover.
Edited to add: Dr Kevin Lehman wrote an excellent book called "The birth order book". Do give it a read.