You need to meet the API Q1 personnel competence requirements in Q1 4.3.2.2 and maintain a record of this. It is very likely that your next audit by API will include them checking internal auditor competency records.
4.3.2.2 requires personnel to be competent based on "appropriate education, training, skills, and experience" and requires "evidence of the determination of competence of personnel" to be recorded and maintained. It is up to your organization how you determine and document competency. An internal auditor qualification to IATF 16949:2016 alone is likely not sufficient, but it is a good start. I'd recommend documenting that you reviewed and/or were trained on API Q1 (not required to be external training) and then create a record which states that the organization has determined you to be a competent API Q1 internal auditor based on your IATF 16949:2016 internal auditor qualification (training and experience) combined with your API Q1 review/training.
Develop your own checklist (instead of downloading one from the internet) and use that for your audit and as evidence of your competence to interpret API-Q1.
You could do this and use it as evidence of your API Q1 knowledge. I recommend having a specific record of
determination of competency which states that you were determined to be competent and the basis (including at least one of education, training, skills, and experience) for that determination. Such a record will greatly reduce the risk of a nonconformance from API related to internal auditor competence.