Further to sashh, also a Btec does not carry the same number of UCAS points as an A level and many universities do not make UCAS points offers anyway ( not to mention may well de select simply because the right qualification - i.e. A level - isnt there.) So its not straight forward B Tec is as good as..... It will limit the course you can choose at university and limit your choice of university (or go at all)
From a personal point I have/ will make all my DC take A level. I do not like B tec. It limits career choice if chosen early (i.e. at16/18). People do not like this said but it is true. I state that up front so that you know.
Yes, you may be able to retrace your steps and go and complete later on as an adult returner. But not everyone does that and its not always financially viable..
As I said before, I have and regularly do take students with a raft of grade C's at GCSE and they make good A levels and good universities in many cases. There are routes at this point for those who do not or who want something different, so all is not lost (a foundation degree is often better than a Btec or HNC). Not all schools and colleges are so obsessed by getting top grades at A level that they refuse to take students with less than A* -B. Many may, but not all.
The usual route pushed for students who have less than this is B Tec. If your DD is not offered Btec its because the school is probably oversubscribed having shoved a lot of its "failures" ( i.e. didnt get Amazing A*'s ) there and filled up the course...... so they say re sit - or they feel that the DD is "academic" and doesnt want to let them be forced into options that might not suit.
When I was at school there were still O levels and CSE. Where I lived there were still grammar schools and Secondary Moderns. Herein lies the tale. A CSE grade 1 was supposed to be equivalent to an O level. My school told me that for 3 years. They didnt do O levels in my school, only CSE. (I came into the school late and there were no places at Grammar school for me to go there). However, I was told, if I did well at CSE and got grade 1 (because it was equivalent and I only needs a grade 1 in my CSE in the subjects I wanted to take ( and a minimum of 5 CSE grade 1 altogether including maths and English Language) I would be allowed to take A level and go on to university if I wanted.
It was only in the last week before I completed my exams that one teacher admitted the truth. A CSE was not equivalent to an O level. It had parity of esteem". It would be on the behest of the grammar school if they allowed me to take an A level on the basis of a CSE grade 1. They usually did not. They usually required at least an O level grade 3 ( that would be probably an A or B now as in my day even O levels were marked on a range of grades 1 - 6 and a CSE was seen as "around the same on a good day" as an O level grade 6 ( and 7 .8 and 9 were "fail") . The following year they changed the grade system on my board to ABC at O level (and D and E were "fails").
A Btec has parity of esteem(that just explains how it worked).
I got 9 CSE grade 1's - Maths, English, History, Geography, RE, Biology, Chemistry, Physics abd Art. I also passed an O level in English Language (which I got at O level grade 3).
Sure enough, the Grammar school told me I had to either go to college and take Btec or I would have to re sit all my CSE's and get O levels.
I know this scenario so well. In the end I went to another college and took A levels, passed, went to university and got a degree. Yes, I did have to work hard because the CSE was not good enough and I did a lot of running to catch up, but I do think it was the best thing.
It may not have seemed so at some points though. When I left university there were no jobs. I went into industry at a fairly low grade (seems like a failure doesnt it?) and my employer sent me on a B.tec. It was very easy for me and I got distinctions. For the next 6 years that Btec gave me a career. However, Btec was limiting. You could only attain a particular grade in the industry and organisation with a Btec. There was a bar. To progress, you needed a degree. Suddenly my "useless degree" was useful because it was a must have to progress.
At that particular time I started a family. When I started work again I went into teaching and of course a degree was a must have. Had I take the B Tec and work route, the degree (nor university) I went to would have been open to me. I would also have found myself side tracked and dead ended in my career (which nearly happened).
My brother on the other hand went Btec and he is now stuck in a technicians job and often says " I cannot progress because I do not have a degree". Taking one as a mature student means leaving his employment (and he has a family too) and he simply cannot afford it financially.
The moral here - and the reason my DC will not take B Tec is simple: Never under estimate how important is an academic path, even if it doesnt initially look it or a different route looks equivalent.
Now of course the options have to be assessed by the OP and her DC, not me, or any of the rest of us. You need to understand where each option will take you and what the limitations are.