The posters highlighting the huge difference between 12 and 11 are right. I was at 11.9 at 16 without training and got put in a race with a 17yo who looked like Ben Johnson. He ran 10.9 that race (I think I ran 12.0) and it felt like I was walking. It was embarassing right from the gun. It's "only" 1 second but it's a totally different world. I wish OP all the best and it's definitely worth the effort. I'm not feeling the vibe though to be honest.