Does being 5 feet as a 17yo boy qualify you as too short?

Yes. Yes. You are probably done growing and going to be short statured. You will not play nba basketball. Its not the end of the world. You still have your brain and hopefully good health.
Depends on parent ht. In the US you would certainly be considered short as a 5' adult. Too short is a relative term, too short for what? Professional jockeys do well at this size. If your parents were short, it is likely expected. If your bones are maturing slowly (X-ray can tell) you may continue to grow into your twenties & add a few inches.Talk your concerns over with your doc if you want to check it out.