I started my flying training when I was 15/16. I wouldn't say I regret it but I wouldn't recommend it to others. One or two days a week flying is really not enough. I often had to repeat lessons as I wouldn't fly for a month. If you are only booking every Sunday for example, a couple weekends of bad weather will really slow you down. It's a waste of time and money.
If you really need to scratch the aviation itch do something cheaper like gliding or read a lot of books. Not just the theory books prescribed by courses but 'extra' ones. Build your knowledge so when you do start flying training after school you can focus on the fun and smash the theory.
The advice to travel is also very good. Once you start in the industry it's hard to take a year off. It's all about currency.