PhD

No.11448714 ViewReplyOriginalReport
I am an undergraduate student (3rd year) in a World top 100 university and currently consider applying to some PhD program in USA (effectively skipping master's). I have an excellent average grade, do some stuff in the laboratory, really love to study, etc.
But I am not fanatically interested in anything. I mean, I look at labs' in my field (Earth sciences - geophysics) research themes, and they all look quite interesting, but there is nothing that would keep me reading about all night long (had such girlfriend once).
Is it fine? Am I supposed to start participating in some project, setting some milestones and then improve in my theme as it becomes my job? Or is it a sign that I shouldn't do PhD?