How can i become a better JV running back please help.?

im 14. and will be 15 when the preseason of football starts. i will be playin JV for high school. last year for freshman football i started kick of return and wide receiver. but since our school isnt a really much of a passing team in freshman and JV i want to play half back this year, and i am not high enough for wide receiver probably. anyways as you can tell im a small guy. currently, im 5"4 112 pounds. i barely bench as of right now, but i will be hitting the weight room crazily after track ends. so as of now, i bench max 102 according to the max bench calculator. im aiming for 5"5 120 bench max 130 before the end of preseason btw. anyways i am the fastest and probably can juke and go through holes the best on my team. so really im trying to be a speed back. but can you guys tell me how i can work and train so i can have a bette chance of startng, or just any tips. and if you dont think half back is good for me, please tell me what other position i should consider. i really dont enjoy playing defensive backs because i like to score a lot more than hitting somebody