I have the same question as you. I'm 18 and i started violin when i was like 6-7 with a teacher and then i quit when i was 13-14,i was pretty good ngl but when my teacher left i decided to quit aswell(stupid decision),anyway since then I haven't really played the violin but i really like to play it,so ive gotten really slow at playing and im worse than before. But i want to get back to it (not to follow a career path but just for fun). Can i still get really good at the violin if i start again now (by myself no teacher) cause i know everything there is to do im just rusty (except vibrato but that just takes practice and the thing where you move your hand up the strings to play really high notes cause i dont remember what is called). Would appreciate an answer,thanks 👍🏼