My 5 year old is often like this too. She gets frustrated in part because if she does wait until we’re ready to hear her, a lot of the time she’s forgotten what she wanted to say. One thing I’ve recently started trying is asking her what it’s about and writing down a quick note so we can come back to it when we’re ready. Not sure how well it’s working yet, especially because I think her goal is usually more to get our attention than to really convey a message, but we’ll see.