I have seen sibling rivalry up close and personal in my friends' lives. It can get brutal.
But Baby A and I just aren't like that. Sure, there were times when either (or both) of us would get a little green-eyed like the monster. But that has not happened in years. Honestly, out of all the twins I have met, rivalry hasn't been a problem. I have heard stories, like "a friend of a friend of a friend of mine is a twin and they hate each other and they always compete" but have yet to hear anything more concrete.
Growing up, it can be hard to constantly be compared to your twin. "If you guys have the same genes, then why is she better at math/writing/running/tether ball?" was one we heard often growing up. (Just so we're clear, Baby A is better at math. You'll hear more about this below). If we ever scored differently on a test, everyone was shocked. "Oooo, that one must be better at history/science/reading/life."
Even now, in college, that happens. In the fall, for chemistry, we were in different sections, but coincidentally had the same TA. As he was passing back the first midterm in chem lab, he said to me "Your sister did better than you." He was very nice, and I'm sure he meant nothing malicious. It's just one of those things people say without thinking about. The fact that he said something about our different scores shocked me, for some reason. I guess I wasn't prepared for it, like I had been throughout all those years. I thought maybe we had left that behind with compulsory education. But as long as we go to the same school (or, in our current situation, university), we will be compared.
When Baby A does better than me in school, I am so proud of her. Sure, I may be upset, but not at her. I compete against myself, and if I feel I could have done better, that's what irks me. Not that my twin beat me on an exam. She feels the same way, that she can be both happy for me and upset with herself, and those two things are not related.
Case in point: Baby A just got a midterm score back from this third calculus class she's taking, and she did much better than she was expecting! I, on the other hand, struggled to finish the second of three calculus classes in the very same calc series. After a particularly bad midterm, I was just hoping to pass and knew I didn't have the heart to take the third quarter of calc. I also decided right then and there that my major was changing. I looked for majors I was interested in that did NOT involve a third quarter of calculus. (Luckily, this new major is a much better fit than my old major, and I'm very excited about it). Yes, I copped out of calculus, it was that hard for me. But my twinkie stuck it out (her major requires all three calc classes) and she's working hard. Her score showed that.
Am I jealous that she did so well? Nope. All I am is thrilled.