In fact, it's entirely possible that no one is more excited about it than the little guy, and that includes the incipient birthday girl herself. On the one hand, I'm proud of my son for having a positive attitude about what must be a tough stretch of the year for him, the mid-March to mid-April stretch bookended by his younger siblings' birthdays, with his own still about half a year away. On the other hand, I suspect it's not entirely selfless of him to be excited about parties and cake and presents, since he more or less gets to partake in all of them even if he's not the one specifically being celebrated. I will credit him for not trying to blatantly make it all about himself, but it usually plays out something like this: he'll announce out of nowhere "I'm so excited for my sister's birthday!" And then he'll turn to her and say, "Are you excited about your birthday?" She'll agree that she is, although honestly she's at the age where anything not in the immediate here and now, even a big special event that's only three or four days away, is hard for her to wrap her head around; she's more likely to be excited that I let her watch an episode of Doc or Mickey before dinner than about what we have planned for the weekend. But having duly checked in with the rightful person whose opinion matters, the little guy will then swing right back into, "Well, I'm excited!" And so he is, and of course I'd rather have him opportunistically enthusiastic than sullen and jealous, or worse.
My wife and I asked the little girl what kind of cake she wanted at her party and she was able to wrap her head around that with great specificity: "Pink and purple cake, with pink and purple icing, and pink and purple frogs." (See, one of my wife's co-workers made us a batch of little frogs, molded white chocolate dyed green, and we decorated the baby's first birthday cake with them, and they were a big hit, so much so that apparently now that is just What We Do for birthday cakes in our family, and the little girl expects hers to be appropriately color-coded.) And when further pressed as to what kinds of presents she would like for her birthday, the answer was in the very same vein: "Pink and purple girl stuff."
As this blog has attested on numerous occasions, my wife and I are really not hung up on traditional gender roles in our parenting. We've never tried to steer the little guy away from dolls or the little girl away from trucks, and we've also never tried to steer the little guy toward dolls or the little girl toward trucks, either. We get them stuff that looks like fun, or that they show interest in, be it walking through the store or choosing what to play with at daycare or the pediatrician's waiting room or whathaveyou. We've bought a fair amount of gender-neutral playthings but that's pure pragmatism; not a statement of (anti?)indoctrination, just simply trying to get the most bang for our buck by amassing toys that sons and daughter will enjoy equally. And yet if some of the grandparents decide that the little guy's Christmas present should be a singing plastic primary-colored workbench and the little girl's should be a singing pastel vanity mirror ... ehh, we let it slide, rather than make a huge fuss about it. (The little girl honestly was never that enamored with the vanity, but the baby? He freaking loved that thing for a while.)
But the safely hippy-dippy follow-your-bliss home space aside, our kids still have to live in the real world, and at some point in the progress from Montessori to kindergarten the little guy latched on to the idea that certain colors were "boy colors" and others were "girl colors", and guess which ones get the feminine association? So he brought those ideas home and communicated them to his sister, and she's internalized them ... to a point. I've noticed that she doesn't completely avoid the boy colors, but she does embrace the girl colors (as evidenced by her birthday requests). And I truly believe that she's actually done in this in a kind of self-defense. It's not that she thinks she, as a girl, is only supposed to like two colors. It's that she's noticed, shrewdly, that her brother avoids two particular colors. She's smaller, weaker and slower than the little guy, so if there's a toy they both want to play with and he's not in an overly generous mood at that moment, the odds are overwhelmingly in his favor in the physical struggle over who gets the prize. But there is no struggle over pink and purple objects; those are hers by default. Apparently she is cool with this, or at least that's what I take away from her seemingly generic request for "pink and purple girl stuff" for her birthday: she kind of doesn't care what we get her, so long as what she gets is hers. Really anything her big brother wouldn't even think of coveting will do.