Skin & acne
Is it normal to have acne at 13?
Very. Acne is one of the most common effects of puberty, because oil production rises before the pores are big enough to cope. It usually peaks in the mid-to-late teens and improves afterwards, though some people keep dealing with it into their twenties.
What this does and does not tell you
This is general information, not a diagnosis. Only a clinician can examine you, take your history and run tests. The same symptom has different causes in different people.
If something is sudden, severe, or getting worse quickly, get medical advice rather than reading on.