Green card concerns if my credit score is low

If USCIS becomes aware of a poor record, it might create psychological unease and could lead to a more thorough review, but generally, an applicant’s credit score isn’t submitted to USCIS, and financial sponsorship is also provided by others around you, so we don’t think this would work particularly against you. (Unless USCIS specifically requests this documentation, they likely wouldn’t even be aware of it.) You don’t need to worry too much.