From August 1st 2018 through the end of the year you would still be a Non-Resident Alien, so you would need to file form 1040-NR ( TurboTax does not support this form) -- see SprinTax ( Turbo partner ), tax professional or your school's foreign student's office.
When did you enter the country with F-1 ? if it is any time earlier than 2014, then you are a resident alien for tax purposes and need to file form 1040 ( use TurboTax )
Which country are you from ?
