Dollhouse of Solitude

Supposedly, kids like babies and other little kids. I read these things in books and magazines. It's like reading about some foreign culture. My daughter... is not fond of other kids. Oh, she'll warm to certain ones, on occasion. Mostly older ones. But most of our social occasions involve a lot of:
"Waaah! She's looking at me! I don't want her to look at me!"
and:

"waaaah! I want to go on the slide!" 

"Okay fine, go on the slide." 

"But he is there! I want him to not be there so I can go there and go on the slide!"

"But you can get in line and go after him! See? Another kid is there now. You'll never get a turn unless you get in line."

and:

"Someone's climbing up behind me on the toy! He's going to push me!"
"He's not going to push you. I won't let anyone push you."
"He's going to push me! I want you to make him go off! I want to push him off."
"No pushing. Play area toys are for sharing. I won't make him get down, but I won't let him hurt you or push you. You need to use your words, not your hands."
"Waaah! I want to go home! I don't want to share the play area!"

She loves her cousins. Well. Most of them. She loves the ones that are 11, 8 and 4 years older than her (but not the oldest, at 16 years older,) and the ones that are 15-17 months older than her. And the one that is almost 2 years younger (still a baby.) She's not so fond of the one 8 months younger. So far, she likes kids to be a bit older than her, or babies. But once they can walk, she's done with 'em. I watched it happen. Like magically overnight. One week at my sister's, Z and Tually are mostly ignoring the crawling Piwu. The next week, BAM! Z is grabbing toys, pushing, yelling and hating all over poor, newly-walking Piwu! Same deal with the next-door neighbors. She loves the 2-years-older girl. And ignored the younger brother (roughly a year younger than Z.) But once he started walking, she started not liking him. At. All.
But she loves babies! Last summer, my other sister, our mom and I took our kids to a beach. Grammelena sat in the shade with 3 or 4-month-old Baby Wivie. Z had no interest in playing in the sand. Or the water. Or on the playground. She spent over an hour playing with Baby Wivie's toes. Cooing and caressing. Asking for a turn feeding her. Crazy cute.
But put her in a room of peers, and she wants nothing to do with any of them. Unless they have cool toys. Then she'll happily play away from any of the other kids. And want to adopt some stuffed animal or doll she's decided she must have.
It's gotten to the point that I just don't go to playdates or indoor play areas (at the mall, community center, etc) or playgrounds, if other kids are there. Even Rywee, the first non-family kid whose name she remembered. I used to be able to lure her into cooperation by telling her that Rywee would be wherever we were going (I'd only offer this if I knew they'd be there. I try not to lie to her.) Now she's not even interested. It's like she's perfectly happy in her little Fortress of Solitude. She'll ask about Appie, and about Tually, but has no interest in doing things with anyone else.
If she didn't at least like those two, I'd be seriously worried. And if a much-older sibling comes out, when I do make her go somewhere, she usually enjoys being around them. And she loves her cousin Taytay (now 10.) Now she'll yell "Oh, Maaaaannnn!" and "You gotta be kidding me!" while watching her kiddie shows, since that's the kind of stuff he says when he's watching his older shows.
And even with older kids, she's only good with one, maybe two, at a time. Have a whole passel of them running around in a play area and she's stuck to me like stink on poo.
I'm not sure why she only likes older kids (must be at least 1 year older. Probably more, since Tually is kind of advanced for her age, and might seem even older to Z.) Maybe she likes watching them, and learning. Maybe they're easier to play with. Less grabbing, and pushing? (Although there's plenty of grabbing with Tually. But then again they've seen each other more than once a month since Z was born, so they've been friends her whole life.) Maybe she just likes the older toys. But now she has all that stuff too. Littlest Pet Shop. My Little Pony. Strawberry Shortcake. Etc.

She's really into books and shows with siblings. Mercer Mayer's Little Monster books with his little sister in them, Angelina and her baby sister. She even calls the Arthur cartoon (on Netflix Watch It Now) the "show with the little sister." She can't play with her little dollhouse dolls unless she has the big sister and the little sister. Too bad I can't just get her an older sibling. Apparently, new siblings pretty much only come in younger form!