I will answer this from a personal point of view as I am a poet. Firstly, good for you! There is no reason why you cannot be a writer, although most writers start off writing in their spare time as a hobby alongside a day job. One common path that has been followed by Heaney,Hughes and many others is to work in a n environment where it is possible to discuss and read. So many of them read degrees in Literature and other subjects such as Classics, History,Arts etc at universities that were notable for this (Oxford,Cambridge, Harvard and many others in the US and elsewhere and then went on to teach/professorships.) Many like Walt Whitman and O. Henry did not have that opportunity though and still made it - but you need a bread and butter job as they had.
Secondly, read poetry every single day. (I read at least two new pomes every day) You will be feeding your imagination and intelligence.Also read widely on other subjects and take a keen interest in world news and politics.
Thirdly - start now! Keep a daily journal,jot down in any poetic phrases that spring to mind when admiring nature,feeling blue or whatever - you can draw on them later. Never copy the style of other poets - many writers were first noticed for being themselves! Don't pay any attention to style, structure or techniques at all at first and don't attempt to 'build' a poem in this artificial way - that can come later when you get to university - we hope! And read,read, read, read,read.......
There are three elements, at least, in greatness.
1. You have to be born with something special. Usually accomplished people are exceptional in some trait - intelligence, ability to empathize, etc.
2. You need to work hard. In this case, you should read a lot. You probably should master the classics - Latin/Greek and the greats in literature.
3. You need to be born in the right time, that is, in a time where your genius is recognized and valued. Hence, there is a timing issue.
I think all three need to come together for greatness to take place, especially of the Shakespear level.