Degree in the UK will leave you with ~£7k per year of government debt (split evenly between tuition and maintenance loans). Probably the reason it is not talked about, is because it is the cheapest loan you'll ever get. Interest rates in 2009 were 1.5%, which in real terms was 0%. There is talk of charging a 'proper' rate of interest and increase fees, so best to apply sooner rather than later.
£3.5k per year of free money, spent wisely, would easily fund a PPL and some hour building.
I can tell you from personal experience that a teenager in the cockpit is frowned upon by the majority of people you come across - be it fellow pilots or passengers. People work on first impressions, and it is a real struggle to convince them that you are capable of safely operating an aircraft. Put yourself in the shoes of an employer; are you going to hire the 19 year old with no proven life skills, or a 23 year old that has been to university and gotten a job afterwards to pay for (or at least contribute towards) their training? I know which I'd choose! As a passenger, who would you choose?
As Seabreeze has said, you will only finish a degree that you are interested in and have a motivation to continue.