At 16 you have all the time in the world, and you can obtain a frozen ATPL for a lot less than £70k. Consider a degree if you're academically minded, as it will open up jobs (and hence funding opportunities) that would otherwise be closed to you.
Once you're working and earning money, you can fly and/or study in your spare time and fund it as you go. Like many people I managed to do my PPL, hours building and ATPL written exams while working full time. It obviously took longer than doing them full time, but it meant I had zero debt - I only needed to borrow money for the CPL and IR.
Typical cost for the modular route - £40-45k.