Welcome aboard!

I dunno why that is really, but I have the same thing. I think it could be to do with the fact that as children we don't actually know that there is an actual concept for lucid dreaming and that it just "happens". Also we might remember them more clearly because at that age, our dreams tend to be amazing as you can do stuff that you know is impossible and over time we become desensitized to dreaming.

If your recall is bad at the moment it's most likely best for you to create a dream journal and jot down what ever you can remember from the previous night.