[speleolinux]

Hi. I always liked science so I went into physics and got a PhD. That led me to work in semiconductor manufacturing, then a national research organisation, some research for small private companies, and now I'm running a small super computer for researchers and helping them to use Linux and get their programs running. I have been able to pivot when needed because all of those fields have intersections and I could use skills and experience from one field in another. If your having problems deciding between fields then possibly shift to deciding based on future supervisors. Are there ones that stand out? Ask their previous students. I have never started a company but have run a small sole-trader business making some electronics. It went OK but not very profitable. One thing though in doing a startup - the younger your are, the less you have to lose :-) Best wishes, I'm sure you will do well in anything you try :-)