John's answer is excellent so to his I'll add what my teenagers say: I suck at school. When it comes to school, I AM a poor student. When it came to school, I was a terrible student.

When it comes to school, I am a bad student. When it came to school, I was a bad student. "I am a bad student" "I was a bad student" "I am a bad student at/in school" "I was a bad student at/in school" Are the simpler easy ways to phrase it without using the construction or phrase 'when it comes/came'. come/comes now came past, it depends what time you are referring to. when it comes to x is the common way, unless you are specifically referring to the past and this needs to be made clear.

When it came to school, I was a bad student. .. CAME past tense of Come. WAS - past tense is is.

Who is it???

I was a bad student, when it came