According to the software that you registered under, you are using TurboTax Free Edition.
TurboTax selects the form that is appropriate for you! It gets its selection from the data that you enter. Form 1040EZ and Form 1040A can be prepared using the edition that you're utilizing.
If you are not claiming a dependent TurboTax automatically uses Form 1040EZ.
If you were to claim a dependent TurboTax would automatically use Form 1040A or 1040.
You can attempt to clear & start over in order to see if this changes anything in your favor. However, if you were to clear & start over all of the information you've entered would be lost
If you really feel you need a 1040, TurboTax Free Edition does not include the form 1040.
In order to get the 1040, you need to use TurboTax Deluxe or above. if you are using an online product.
Any CD or Desktop version from Basic and up will do the 1040.