At one point I actually realised I messed up the timeline (the years didn't add up).
It would have been too difficult to change it afterwards, so I sat down and figured out how to "fix" it - I added a twist to the character's backstory, so that those extra 2 years made sense. This kind of changed the plot, but it gave me an idea that later became the most important plot point of the story.
So before thinking about restarting, you should really try to think about ways you could "make the mistake canon"! It might give you great new ideas.
(However, I can relate, I would loooove to redo at least the first chapter, because at that time I did not know what I was doing and there are so many things I would do differently today. But yeah, I posted the first chapter like 3 pages a time, so it's not like I'd have to replace only one update...:') So I guess I'll have to live with he original version. )