I'm only in Y12 so can't give incredible advice, but marketing is what I want to go into as well. From what I've seen with uni requirements, they don't tend to need any specific A Levels for marketing. With Psychology you've probably got an edge, with it linking with consumer mindsets and such and having to carry out research in a marketing career.
A Digital Marketing Degree Apprenticeship is what I'm planning on. No loans to pay back and a kickstart into the career with actual work exp sounds great but it'll take a hell of a lot of prep as they're very competitive. There exists combined course options in psychology/marketing, business studies/marketing and management/marketing. Plus there's pure marketing degrees that, paired with some work experience in your free time or a placement year, would be relatively quick in getting your foot through the door too.
Here's the uni courses related to marketing I've got my eyes peeled for if applications for degree apprenticeships go south (they're all pretty high ranking):
- Management/Marketing Uni of Bath
- Marketing/Business and Management/Marketing Uni of Durham
- Marketing Uni of Liverpool (my fave option, the module choice is pretty sweet imo and lets you customise your degree)
- Marketing at Uni of Bristol
- Marketing/Management at Uni of Exeter
- Advertising/Marketing, Business and Marketing, Marketing/Management Uni of Lincoln (they do a Buisness Psychology course too)
- Markeing/Buisness Management at Uni of Keele
The ones I gravitate to are based on my interests in digital marketing specifically. You might be more interested in psychology joint courses for example.
What I'm planning on doing over summer and any free time in my second year...
-Volunteering or doing an internship. Glassdoor, Indeed, LinkedIn and DoItOrg are good places to look. Heck, I'm sure if you ask local businesses that may be struggling after COVID they'd be happy to take a free employee that might help them market their services.
-Finishing Google Fundamentals of Digital Marketing course (it's free if you want to complete it and get a certificate)
-Trying to experiment a bit with skills that link into marketing. Journalism courses, copywriting courses, designing skills with Adobe Creative Cloud suite, teaching myself some more HTML/CSS... There's a ton of different specialties you can have in marketing and carving out yourself some specialised skills early on can't hurt.
Best of luck in your search! I'm feeling a bit stressed about UCAS and applications and careers myself, so it's nice to see someone else interested in marketing