Can you be bad at meditation, or fail at it?

There is really no such thing as being bad at it. If your mind wanders a hundred times and you notice and return a hundred times, nothing has gone wrong, that is the exercise working exactly as designed. The feeling of doing it wrong almost always traces back to expecting a blank, blissful mind, which was never the goal. Every session counts, including the messy ones, and especially the messy ones.