Now Im quite the newbie still but I think my biggest advice is just start! Just do it!
I regret never starting earlier, like years ago, caus I was always scared of never being good enough, I cant draw this or that but since I started drawing my comic I've learned so much while doing so yeh, just start and dont start over - keep going 
Maybe start with a smaller project, something you can finish maybe within a year or so, and take what you learn from it with you to the next project 