Hammerthrower
It's good to see someone of your age looking towards a career in ATC. If you haven't already done so I would strongly urge you to visit ATC at Glasgow Airport and also go down to Ayr and visit the Scottish Air Traffic Control Centre. I would also encourage you to stay with your idea of going to university. The job of ATC is becoming more and more technical and specialised as traffic levels increase and if you have a degree in Aerospace Systems and are a fully trained ATCO then the world will be your oyster.
I first wanted to become an ATCO at about your age after a visit to the Southern Air Traffic Control Centre at Heathrow many years ago, but didn't get the opportunity to become an ATCO until I was 23 and that was in Australia.
Follow your dream and all the best with achieving it. Let us know how you get on.