ADC main help (very low "elo")

Hey guys I'm a very new player here. I'm level 30 and only have 165 wins. My main role is adc and I'm trying to main Vayne. My win percentage with her is not so great, I only become useful to my team late-game and get crushed early game. Mechanics are basically non-existant for me but I think I do decent with the some other fundamentals in the game (map awereness, CS, warding). I was wondering if I should stop trying to learn Vayne and find a more "user-friendly" adc to learn or if I should keep maining her and become a one trick pony?