How will new kittens affect my older cat?
You are absolutely correct to be concerned about introducing the kittens to your older cat. You can make this easier by making the kittens smell like they belong by rubbing the older cat’s blanket on them and rubbing them with some of your dirty socks. This will make them smell like they’ve been there all along. Consider setting the kittens up in the bathroom so they can get acquainted under the door. While this is going on, pay plenty of attention to your older cat so there won’t be feelings of abandonment. Lots of times if there is a great age difference in the old and new, it really works out better. I’d give it at least 3 weeks, maybe more.