If you are considering university to obtain, for example, a Bachelors in Computer Sciences, then you will should definitely be putting the nose to the books. They'll look at the grades from your senior years (they'll ask for your transcripts when you apply), and the higher the better.
The other route you could consider going is the certifications route, which doesn't necessarily require high marks (though a solid education is recommended). Take a look
here for more information.