Every bot team will win on blue side and lose on purple side - that's how the AI is programmed. However since league games are randomized at the start of the season, there's no telling which side/leauge games will be played first. If you had gotten into the season later, you might have gotten better or worse stats.
I know it might be frustrating, and it'll take a whole season more before you advance - but hang in there! There might be light at the end of the tunnel :)
Hope this clears up any questions you might have regarding this.
EDIT: By completely random, i mean you overtake a numbered botteam that's next in line afaik. But the win/loss ratio is completely random as i explained.