As one dreamer who will be 30 in November I suggest taking an afternoon to consider what kind of life you want to live and decide what the first steps on that path will be.
Although secondary school will soon end, this really is only the start of modern life.
(After all, modern medicine is able to promise us 90+ years now)
From here on the challenge is to live a life defined by your own intentions. Many others have their own ideas about what your life should be but it was not so long ago (<1000 years) that everyone mostly did whatever they liked to the extent they were able.These days we see that most people follow a pretty well defined pattern in life.
While that does bring a relatively safe predictability to society, it also does it's damned'est to squelch the unique perspectives that make you who you are.
Whatever the challenges you face ahead, please feel free to make your own vision for life a reality.
The world waits to be impressed by the shit that you dream up, as long as you have the will to show us that it can be real.