NewUserHelpMe
Academic ability is largely irrelevant. You will find people with very well regarded academic degrees on the course along with people straight out of school. Most tagged schemes have academic requirements but it's mainly a box ticking exercise to make the sift. What's far more important are your 'non-technical skills' i.e. the examples they ask for in an interview, such as teamwork, leadership, problem solving etc... It's well worth taking some time to sit down and think how you would answer these questions using a recent specific example of a time you have shown these competencies.
I agree entirely with john_smith's last paragraph. The learning curve is steep, some people believe once you've done ground school it's the hard bit done. The flying definitely is the funner part but you will need to put in the effort to see results. It's no use coming back from a flight that didn't go well and say 'it will be fine next time' then proceed to go out on the lash that night! You will need to thoroughly debrief yourself: what went wrong? Why? How can I stop it happening again? It's a constant cycle of self-assessment and improvement, it can be tough but it needs to be done to achieve results. Nothing will annoy an instructor more than if you turn up not having done the required preparation. It's just very poor and shows a very bad attitude. Can you handle the work it is the question you need to think carefully about.