How would I tell them?

We have been ttc for almost 3years (unexplained fertility issues) but for the first time we got a positive opk (currently 2dpo) I'm trying not to get my hopes up too much but I been thinking about how I would tell them. I want a really creative way to tell my husband as soon as possible but I want to do something special. My daughter will be 9 in October (previous marriage) so I was thinking of telling her at her birthday party when it's just family. She's been really excited about getting a baby brother/ sister and always asks me if she will have one soon. The only thing I can come up with for her is a tshirt that says big sister but I feel like that's done all the time and just want to do something more. Our families know we have been trying for a long time so it would be a big moment. I would love to hear your creative ideas!