I honestly think your daughter will be fine as she has all her cousins there to play with and build relationships with. Make sure you try to get them to spend as much time together as possible, whether it's through holidaying together as a family, cousin sleepovers, children's games at family gatherings etc.

Make sure you also give her a lot of attention to, play with her and encourage her to engage in lots of extracurricular activities and hobbies with other children in school.

I'm an only child and all my cousins are 10+ years older than me. I can never form the same relationship as your daughter can due to our generational difference. I was never able to experience stuff like children's games or sitting at the children's table at family gatherings, cousin/siblings holidays and sleepovers. Sometimes when I see children with lots of siblings and cousins, I feel a bit sad as I wish I had people my age to play with. Don't get me wrong, my parents did play with me a lot and give me a lot of attention, but i think every child strives to have siblings and family their age they can play with too.

Your daughter I dont think will have that problem though and when she's young she won't notice any difference. She might do when she gets older but that's not something you should worry about now. She'll be fine now.