Heres my advice-
Only do 3 full A-levels, it is way to much work to do any more than that and tbh it wont give you much of an advantage. So either drop two AS's for A-level or just do 4 AS's and drop the one, the latter is the conventional way of doing things (of course your school may be different!)
If you have a choice at your school only choose English Literature do that instead, as it is more respected than the language or combined language/literature course.
If you want to be a barrister you should be aiming for a 2ii at a very minimum (tbh it should be a 1i) and then join one of 4 inns of court, do the Bar Vocational Course (BVC), and get called to the bar. You then need to do a pupillage where you shadow a barrister for a year.
So in all it takes about 2 years after your degree to become a barrister.
To be come a solicitor you need to do the Legal Practice Course (LPC) which is one year. After that you can start practicing law with a firm.