In my experience the T-shaped approach that others have mentioned is a good one for the long term. Become an expert in one thing you enjoy but keep being useful

In my experience the T-shaped approach that others have mentioned is a good one for the long term. Become an expert in one thing you enjoy but keep being usefully employable in most areas. I'm naturally a generalist, I enjoy every and all parts of creating network/computer/OS/userspace systems, their performance, operation and security. But I've also specialized in some areas. As I get older (about double your age) I have held very high level generalist roles, but those start to become few and far between up the corporate ladder. In my more specialized role, very senior opportunities are more common since not so many people seem to specialize.