The admins can delete a user totally, but all your posts just get renamed to "Unknown" you only posted 14 times so I wouldn't be very concerned, just go quietly into the night.
I believe you might be able to see your post history and delete all of your 14 posts you have made, I know in PhpBB you can but am unsure what software this forum is running.
But I honestly would say, don't worry. Now if you have a face book account, that information being out there I would worry about
Edit: Well I had a peek, you can click on your profile button and then select "See all posts" While you cannot physically delete the post you can edit them to have no text.