If you don't want to do compsci at uni. DO NOT TAKE COMPUTER SCIENCE A-LEVEL.
If you want to do compsci at uni, try take Maths and Further Maths first. The non-exam assessment for 2nd year is very challenging as you'll have to learn beyond the scope of the spec, in your own time, with little guidance, all for 20% of the final grade. The effort is simply not worth it, so I advise you drop compsci after AS if you take it - unless you already know how to develop software. My friend did the same and he has gotten offers from Bristol/Southampton/Warwick.
The non-exam assessment is a very good learning experience but you will have to go through many hardships as a result. With little experience you will be just suffering unless you're super committed.
The theory is pretty easy once it clicks. Programming is also quite easy if you had past experience. Skeleton code might be confusing for some.
The main problem with the subject currently is the lack of relevant resources and guidance for A-level specifically. You might find yourself learning uni level stuff online sometimes.