My standard deduction is 6k and change, but shouldn't it be 12k? I'm filing as single for my 2019 taxes.

Can you be claimed by someone as a dependent? Then your Standard Deduction for 2019 is limited to the greater of:

1.  $1,100, or
2. your earned income plus $350 (but the total can't be more than the basic standard deduction for your filing status: $12,200 for single).

To review if you selected to be claimed as a dependent:

1. Login to your TurboTax Account 
2. Click “My Info” tab in the black bar on the side of your screen.
3. Click “Edit” next to the name.  
4. Scroll down to the first question in Section 3: “A few other things we need to know”
5. Review the question "Someone else can claim me as a dependent on their tax return"

If you are not claimed as a dependent please ensure that you are not itemizing:

1. Login to your TurboTax Account 
2. Click "Federal" from the left side of your screen
3. Click on “Deduction and Credits” tab on top
4. Scroll down and click "Wrap up tax breaks"
5. Continue until you get to the Standard Deduction versus Itemized Deduction page
6. Double-check which deduction you selected and if needed change it by clicking on "Change my deduction"