Usually a 2 year course with formative and summative assessments and associated coursework, although late starters can still achieve.
Your next steps...
You could take this course either alongside, or to prepare for, a GCSE in Art and Design or an equivalent vocational qualification in a related subject. You could go into a job related to art and design by doing work based training. This could be through an apprenticeship where you will gain relevant experience and qualifications such as an NVQ whilst earning money at the same time. You could also go straight into a job as the course will provide you with the basic skills and knowledge that many employers are looking for.