Parent here with 2 boys, ages 6 and 2 :). I have some good news for you if you're worried about planning! I was wondering the same things before they were born, but it turns out that children will develop their own interests and are much happier digging into what they are interested in. The best thing you can do is help support their interests! They will also see what you are doing and want to follow along too.

Don't worry too much about planning things out, because the any grand parenting plan will go out the window once they baby arrives haha