If you want to perform better you need to get stronger. Now not all positions have the same needs in regards to body composition. But one thing that will not hurt you at all is trying to improve the way your body moves, looks and feels.
If your goal is to hit the ball harder than you need to generate more force. Force equals Mass times Acceleration, therefore if you're small and weak aka lacking mass then you need to lift and train for that. On the other hand, maybe you have to much mass and need to lose some pounds to accelerate faster.
No matter what age you are you have to get your body in shape, so you perform like a well-oiled machine. If you get stronger, lose some weight, gain some speed this will only increase your performance making the game more fun! The time is now for you to go out and find a way to train as all great athletes have done!