The 6th form I moved to for a-levels made students take 4 and more than a half of the students did an As in the 4th subject. I was a clueless, naiive soul who 'loved' all my subjects equally and did not do an AS; in reality I was too scared to do an AS because I didn't want to do exams I did not feel prepared for. You might end up feeling the same way. If you want to get grades and not cry yourself to bed every other night, take 3. If you are smart and can manage time, you will be fine with 4 but without interest you wont want to put in the effort. Do yourself a favour and like some other person said, STAND YOUR GROUND. x