I think you should ask why you want to "get in to CAE" if you are still confused as to which training to choose and commence. Under the previous licensing system the UK CAA stated in Standards Doc 35 that:
"The minimum educational standard expected of a student attending integrated courses is that the student will have obtained the equivalent of at least 5 passes in General Certificate of Secondary Education examinations (GCSE) at Level C or above, including English Language, Mathematics and a science subject, which need not be physics. It is for the FTO to advise persons who do not meet this educational standard on their admissibility for the course they wish to undertake"
I'm not certain that this is expected any longer as a pre-entry requirement for an EASA Integrated CPL course however so this would be a useful question to ask your chosen or potential training provider. I'm not very familiar with BTEC's either so is this something you are taking post-GCSE?
It's not 'pretty hard' to get into CAE but it is pretty hard to achieve a successful outcome if you venture into an integrated course unprepared. If you are interested in the modular path I would suggest CAE is probably not the path you want to take in terms of obtaining a PPL and attaining the hours requirement for the CPL module for various reasons. Essentially though, all this information is available from forums such as this one and importantly, from the training providers. If you have attended open days as you say, is there not an opportunity to ask questions? I also think you do a little research into what airline flying entails as you sound a little naïve although I take full account that you are likely to be youthful.
Unless of course I am being naïve and you are in fact a troll.