Haha, congrats!
And don't sweat it too much, almost everyone has that problem with their first few LDs (unless they were a natural as a kid I suppose)

I can't really think of any decent advice to stop being excited, it just takes some practice.
But one way to keep the dream stable is to heighten your experience of it ... run your hands over the floor and feel every little bump, taste the air, etc

At least that works for me sometimes.. but maybe that's the wrong approach for this, as the dream is probably already very vivid, not deep and sluggish.

So yeah, I reckon it's just a matter of practice