i am 13 12.5st and 6ft 1, i am a tall novice amateur boxer, ( i will be getting fights soon), i havent sparred much and if i do its always with expirienced adults, my trainer tells me sicne i am tall i should use my jab lots but people always see it coming, its decently fast and i dont think i telegraph it, any help
Keep your left hand moving and throw a lot of feints with it and/or your left leg. Vary the speed of it (slow slow slow fast fast) Throw to the body and head in combos. (1-1b-1-2) Hook off your jab.
Then likely you are telegraphing with it indirectly. It could just be a small thing such as your eyes, change in your position slightly, a pause, or your timing / range for throwing the jab is predictable. An experienced fighter may read the cue and will react before you even threw the jab. Better if you ask your grown up sparring partner what you are doing wrong. You're not competing with them so they should have no problem giving feedback.