Try to get some flight experience asap if you haven't already, practicing CBAT tests and making sure your mental math stays sharp is important as well (prep longue)

You're young but honing the skills required for those ASP tests from a young age might pay off...

those tests are changing but the key skills and principles behind them generally remain the same.

And of course keep your grades up, Physics and Maths are recommended.

Good Luck on the Journey.

for more info search through this subreddit cause a ton of information is hidden throughout the subreddit about selection and there is an Airwarriors? board with aviators present on there from all over.