If I had no social security taxes withheld because I'm a teacher how does turbo tax account for this?

Enter your W-2 as received.  

Social Security taxes withheld are not entered on a tax return.

You just do not enter anything from the blank boxes on your W-2.   TurboTax and the IRS are well aware that many teachers do not pay in to Social Security because they pay into a teachers retirement system instead.  The amount that was withheld from your pay will usually be in box 12 of your W-2 and you will enter it from your W-2.

Teachers and Social Security

There are 15 states (AK, CA, CO, CT, IL, LA, MA, ME, MO, NV, OH, TX) in which teachers do not pay in to Social Security, so you will not see Social Security withheld on the teacher’s W-2.  Instead, teachers in those states pay in to a Teacher’s Retirement System, which will show up elsewhere on the W-2 often in box 12 or box 14.

There are three states which have varying degrees of participation in SS for teachers, depending on school districts—GA, KY, and RI.