Hey dude, I am also in high school (17) and 160lbs, and in fact have a training log called high school powerlifter, pretty similar to the thread name lol. There isn’t any minimum strength you need to compete at a powerlifting meet. You get to choose the weights you lift. Make sure you lift to competition standards in the gym. (Squat depth and commands). Also, I’ve never log pressed, but 540lbs x 8 is definitely a world record, maybe you mistyped that. Also, you wouldn’t happen to train at Neversate Athletics, would you? I know it’s a pretty awesome looking gym in Maryland run by youtuber (and tnation forum user) Brian Alshrue. Let me know anything you want help with! People will definitely be able to help your squat become pain free from seeing form videos. Other than that, make sure you’re running a solid program, and you will be super strong by the time you’re my age!