I'll start with the criticisms, and then move onto the good.
There are a couple of mistakes: "I would feel different if there was anyone you hated here,"
Should be: "It would feel different ..."
And: "They only grow during the last few weeks of fall"
Fall is an Americanism, it should be Autumn :)
"I'd like to help people notice the things the"
Should be a y on the end of the.
"And... my mom and dad too, I bet."
Mom is an Americanism. We use 'Mum'.
Now. I really enjoyed this story, it's lovely and gentle and very enjoyable. Luna's characterisation is very endearing, and I really like the moment they share under the tree at the end - so like the end of OotP. I also like the way you've weaved this into book six canon. Luna's views on commentating were brilliant :D