should i change colleges and retake year 12

i'm currently in year 12, and have began to regret not taking A level graphic design in a different college (my college doesn't offer it). i would like to do graphic design at uni but i don't think they would let me because i'm not taking a creative subject right now.

is it a good idea to try and change to the other college, and start fresh with 2/3 new a levels in year 12?

A few pointers regarding the above:

See the links below regarding roles in graphic design:
https://www.getmyfirstjob.co.uk/?TabID=1358&id=1378&occupation=graphic-designer
https://www.prospects.ac.uk/job-profiles/graphic-designer
https://www.careerpilot.org.uk/job-sectors/design/job-profile/graphic-designer
https://www.dba.org.uk/careers/graphic-designer/
https://nationalcareers.service.gov.uk/job-profiles/graphic-designer

If you look at the entry requirements for graphic design degrees below, you would find that they don't require specific A Levels:
https://www.uos.ac.uk/study/ba-graphic-design/#d.en.23187
https://www.ed.ac.uk/studying/undergraduate/degrees/index.php?action=view&code=W210
https://www.ntu.ac.uk/course/art-and-design/ug/ba-hons-graphic-design#entry-requirements
https://courses.uwe.ac.uk/W211/graphic-design#entry
https://www.aru.ac.uk/study/undergraduate/graphic-design#entry_requirements
https://uel.ac.uk/undergraduate/courses/ba-hons-graphic-design
https://www.mdx.ac.uk/courses/undergraduate/graphic-design
https://www.aup.ac.uk/courses/undergraduate/ba-hons-graphic-design-jan/entry-requirements
https://www.arts.ac.uk/subjects/communication-and-graphic-design/undergraduate/ba-hons-graphic-and-media-design-lcc#application-process (slight preference for specific subjects, but they're preferences not requirements)
https://norwichuni.ac.uk/study-at-norwich/courses/ba-hons-graphic-design/#entry-requirements
https://www.art.mmu.ac.uk/graphicdesign/
The above is just a sample, as there are more degrees to look through.

I would have a portfolio ready even if unis don't ask for one, because you would need a portfolio to show to prospective employers after uni.

Do note, graphic design isn't an academic subject and there isn't a huge queue of applicants applying for the courses (e.g. not top end unis for academic degrees). There are usually a good number of places available on each degree course. So long you are able to meet the grade requirements and say how interested you are in the subject + whatever ambitions that you have, you should be fine.