I applied in July, and I got my work permit this month . I also had very little evidence to show. I had no work history, no bank account, and I graduated from school in 2008. But I went to Mexicana Hermandad here where I live, and they really helped me pull every bit of information together. Such as, a few doctor visits I had, receipts of medical pprescriptions, gym membership receipts, volunteer work... so long as I didn't have empty history that stretched more than 3 months, I was fine.