For starters, I have absolutely no knowledge of University of Michigan.
But I hit the school website, looked at your major, and found this:
https://lsa.umich.edu/content/dam/psychassets/psychdocuments/MajorInBCNPsych/BCNConcWS_7615fillableupdated_8317.pdf
The odds are that you’ll meet with an advisor before registering. But, just in case I’m wrong, here’s what I would suggest:
Take the 2 prereq courses listed at the top of the sheet. 4 credits each, so far that’s 8
OK, that’s one Psych and one math.
You’ll need to take the first year writing course https://lsa.umich.edu/lsa/academics/lsa-requirements/first-year-writing-requirement–fywr-.html 3 more credits, so far that’s 11
You’ll eventually need a language, I think that’s 3: https://lsa.umich.edu/lsa/academics/lsa-requirements/language-requirement.html So you’re up to 14.
I would look for a light, 2 credit course
https://lsa.umich.edu/lsa/academics/lsa-requirements/area-distribution-requirement.html to round things out.