Very nice, I have seen these kind of images in other forums where mostly portraits have been tried in this concept. If you ask me, perhaps I would also have made another frame going a little closer to the opening and try to gain a bigger inner window just to give some more importance to the nature held within walls concept or nature beyond the boundary feel. It could have been a half -half frame too. Had there been a small plant with a flowering plant visible through the inner window as a subject of portrait, may be I too would have thought of this frame. Many frames of this possible, beautifully seen.
Technical things are important too, at times it is possible to go back the next day and reproduce, but in nature in most cases you will never be able to go back to reproduce. So it is always good to be prepared. I know it's easy saying this but now I do not wish to see a part of photography you have left unattended. You would be a pro in a few years, even if u are awaken in the middle of the night and asked to make an image, it has to be bang on, no more of I did not have this or that. Sometimes you can be innovative on those aspects as well. I read in a book that Satyajit Ray's Trilogy of Apu ( Oscar winner ) was shot by keeping the movie camera on a sitting stool, he did not have a tripod. If possible see some of Satyajit Ray's films, they will give you immense knowledge and ideas about camera angles, frames etc. Now you might be a young boy but you certainly do not have the mind of a young boy, so let me treat you like an adult from now on
. Good luck.