New kitten won’t play with older kitten

Hello! :) I have a 10 month old kitten named Suki. About a week ago, we adopted a 4 month old kitten & named her Mila. At her foster families house there were other kittens around her size. We did the slow introduction thing & they’re totally cool with each other (thank god)! Of course Suki hisses or swats every once in a while to set some boundaries, but generally have really liked each other. Mila is super playful with toys but will not play with Suki. Suki is a super chill cat, especially for being a kitten, but she totally wants to play with Mila & she won’t play w her. Does this just come with time? Is it a size difference thing? Does she just not like Suki? We’ve only had her for 10 days, so still fresh. I’m just surprised that the younger kitten doesn’t want to play! I’ve included a photo for size reference. Any thoughts?

Hello! :) I have a 10 month old kitten named Suki. About a week ago, we adopted a 4 month old kitten & named her Mila. At her foster families house there were other kittens around her size. We did the slow introduction thing & they’re totally cool with each other (thank god)! Of course Suki hisses or swats every once in a while to set some boundaries, but generally have really liked each other. Mila is super playful with toys but will not play with Suki. Suki is a super chill cat, especially for being a kitten, but she totally wants to play with Mila & she won’t play w her. Does this just come with time? Is it a size difference thing? Does she just not like Suki? We’ve only had her for 10 days, so still fresh. I’m just surprised that the younger kitten doesn’t want to play! I’ve included a photo for size reference. Any thoughts?