If you just installed it why do you need to export bookmarks? And, as has been pointed out, there are extensions that add that feature. Opera is still very much in development and it is basically the youngest of the browsers out there from a code perspective. It takes times to add these features and make sure they work.

Exporting bookmarks would seems like a basic feature, don't you think?
Especially since they have it since Opera 12.

Regardless whether it's a new or old install, his point is that such basic function should be native to Opera.