Computer Studies as Private Candidate

[Saud Afzal]

My school lets us choose between Biology and Computer but I want to do both, so I chose to study Biology at school and Computer as a private candidate.

First of all, is this a good idea? Is computer hard?
And secondly, what textbooks should I use?
Will I be able to cover the syllabus before the May/June 2014 session?

Thanks