Training legs is very important and actually vital for upper body growth! Just because you can't show off your legs as much in public as your arms and chest they are still an important body part to train! One reason is because it will give your upper body rest, but keep your body at work! #2 Training legs will keep your body well balanced. You wont look unportioned. People think they can just go to the gym and do bicep curls and get big. NOT THE CASE! IF TRAINING WAS THAT EASY EVERYONE WOULD DO IT! Do your sets of squats, do your rows and split squats! Be sure to hit the hamstrings and glutes! It's never to late to train legs. Sure your body will be sore the next day, but you wont regret it! It's like math you can't solve an equation without first knowing the formula to solve it. Well legs are your formula it's time to start training them.