Oh man, two years is such a long time to keep doing something that's hurting you! I get why though, when a movement feels natural it's hard to believe it's wrong, and rounding your back kind of feels like curling up safe, you know? But here's the thing that makes it worse than people realize, every single rep you do with a rounded spine is teaching your body that shape, so those two years weren't just neutral time, they were two years of practice building a bad habit deeper into your muscle memory. Your mentor probably saw it right away because he'd already been where you are, and that's the frustrating part, the advice is free and right there and we still have to learn it the hard way. What finally made you listen, was it an injury or did something just click one day?