Anke
I think you should be very proud of a site like that from scratch. Sure, as has been mentioned, there are ways you could improve it - there always are - and your site will be an ongoing work and will change and improve with time.
Ronnie's point about your exit link is a good one. People will always click your exit link so you might as well make some money out of them! I use Warning Pages -
http://www.warningpages.com/index.php
Good luck!