I'm sure you could if you wanted to, but are you sure it's the best path for you?
A-levels are a lot harder than GCSEs; you may be just passing subjects now, but that doesn't necessarily translate to passes at A-level.
Are you interested in Animal Care, Hair and Beauty, Catering etc.?
A good college diploma could give you much more employability and better future earnings than not great A level grades in soft subjects.
I know someone who wanted to do A levels, but didn't get into sixth form; she's now doing animal care at college and has realised it was the best thing for her. She always hated exams - now she's assessed completely by coursework.
She just needs to do a 1 year course, then she can become a veterinary nurse!