I was exactly in the same position at 18 I'm 23 now. I decided to get my degree and do my flying. Difference is I chose modular training as it fitted in during my summer breaks at university really well and there weren't any cadet programs at the time.
It's an excellent backup too as I've had to use it to get a really good job outside the industry to support my hour building and actually having a life other than aviation.
Most of the cadets on current cadet programs are degree holders and the average age is 25.
My advice. Get a degree in something you enjoy and take the time to get your PPL through the University Air Squadron if you're in the UK or similarly otherwise.