"Last year I made 12000"
Totally irrelevant to the question at hand. What you made last year has nothing to do with this year.
If your W-2 is your only source of income for 2017, then if any taxes were withheld the only reason you would file a return would be to get those withheld taxes refunded to you. However, if you chose not to file a return, the IRS will have no problem keeping those withheld taxes.
