Why do these threads always meander through topics on the roadside?
Back to the topic. First, we have not enough information to really judge what happened the day the poster did not go solo. It would be interesting to have the FI opinion on it. We can speculate on a couple of things, though.
I find it unusual to have a student with an announced go-solo. I would not do that, but it might be part of the game. If there is an overconfident student, you have to ground that brain, so it may be a lesson to cancel go-solo for that pure reason. It may be bad weather, but why was the solo pre-announced? It may be deficits on handling stick&rudder. It may be just a bad day and the lesson to learn was to learn how to mentally cancel a flight? In my surrounding, go-solo is usually a normal pattern exercise lesson at which after at least three patterns FI is confident the student is ready, just leaves the plane to let the student make three pattern solo - no announcement. My personal case was a bit different, though. I had a normal check flight, couple of patterns in quite some bad weather, and after pattern exercise FI told me that he would have let me do solo, if the weather wasn't that bad (OVC006 15kts pure cross). So, he offered me to go solo the next day, which I happily excepted.
No, you are not per se a bad pilot upon canceling your first solo flight. Your instructor was just not feeling right to let you go and my advice is, trust his experience and intuition.