What qualifies someone as an ESL?
He learned English as a Second Language
What if you were born in another country, then moved to the states, your parents always spoke to you in that language at home, you were in ESL in grade school and only learned English once you began school BUT you don't have an accent. Does that count?
If English is your second language, yes. Who cares about accents?
What age did you need to learn English to be considered ESL?
It doesn't matter. Older people obviously have more difficulty, but ESL stands for English as a Second Language, not English as a Second Language Over Age of Twenty (ESLOAT)
It's a pretty simple definition. I don't understand what you're getting at. Did AMCAS add an ESL classification this year or something?