OP, I'm in a similar situation.
My DD just doesn't fancy university. I was really worried when she started talking like this because, for me, I've always seen education as the only way to do better in life. I'm not well-educated so I guess I hold education on a pedestal.
She doesn't particularly know what she wants to do. Rather than a horse, she's into make-up and is talking about becoming a make-up artist. Unlike your DD though, mine is quite keen to move away and do some travelling.
Everything in me wants to shake her and say "Just go to University you daft mare" but actually I think that'd be a terrible thing for her to do. She'd be paying £9K to do a degree that she wasn't motivated for, wasn't particularly interested in and would be likely to under-perform in. That's just daft.
I spoke to a friend who is actually a university admissions tutor (a lecturer who does admission stuff I mean). Her advice was that university will still be there in 5, 10 or 15 years time if/when DD decides she wants to go and as long as she wasn't applying for a massively over-subscribed course (like English or History) then there'd be no reason she wouldn't get in.
However, she might decide that she never wants to go to university and that's fine too. I've come to the conclusion that being happy is all that matters.
Encourage your DD to look at training/jobs with horses if that's what she wants to work in.