Hello Gabs_ and welcome !
Well, I downloaded your track mainly by curiosity and thanks to your screenshot which shows incredible lap records ! (less than 1 second ?!
)
So in Track Editor, I saw you put only one checkpoint for the whole layout. You may put your first checkpoint when there is a curve and let enough space in the exterior, less in the interior to avoid cheating, with your last checkpoint on your finish line, like the screen below :
You may put also some objects like sunk tyres or bushes (with some sand but not strictly necessary) inside the checkpoints, again to avoid cheating.
Also, you put in reverse order the starting positions, so when you start a race, the first one you put on the list will always start at the last place.
And I think you made AI line with the Track Editor, but you may make some laps on your circuit first, then return to Track Editor and import AI line. It will be better that way.
The layout is ok, no problem on it. Good worldsize.
The only thing which really disturbed me is the fact that you surrender your layout by soft walls and trees. Trees, if put at random places on the map, would feel so much more natural, and you don't have to worry too much about cars leaving the circuit. Deleting the soft walls is a good idea, without removing the fun.
It's much or less technical matters, but it will greatly improve your track and people will enjoy your creation more.
You may learn how to do dithering on the tutorial section, and how to fill those empty places all around your track and some basic tips to create a track. Some software like Gimp or GRMHEdit may be really useful later if you want to continue.
Please fix these problems and please keep up your efforts on your trackmaking. It will be worth it.
!