French is a given, not because she enjoys it, but because she's good at it and her predicted grade is a 9. She doesn't like anything else
At that age it's fine not to rush. She's got time to find her way.
I decided to get a job after my gcse's, my parents supported me as I was so headstrong. I had a string of top GCSE's , but I didn't want to study, it sounds like your DD is the same, no-one isn't interested in anything else, but she may be sick of studying.
After two years of working ( fun , but dead end jobs in a record shop, working at a music festival, intern at a video production company, etc I decided to go back to college and do A levels and went onto a top university.
Stephen Fry failed his A Levels, went on the run with a stolen credit card and spent 3 months in prison. He then re-took his A levels and went onto Cambridge and stardom.
Its not all or nothing at 15/16, take a step back, if she's not interested in any A levels, why are you even having the conversation??