Second date? Almost always. First impressions are powerful, but not always accurate. Usually, it is worth meeting again. Oftentimes, it is only on the second date that the potential for the shiduch is recognized.
If you feel that you did not present yourself fully, for any of the above scenarios, or any other reason, let the shadchan know. They can then help the other side better understand the dynamics.
But sometimes, you just know that it won’t lead to marriage. Be honest with yourself about your reason. If you see right away that you have different values, then that won’t be a suitable match. If it is because the conversation didn’t flow so well, or you didn’t like the way they looked, or something they said, then it might be worth meeting again to get a more accurate picture.