And this is the first year you placed it in service?
If so, unfortunately, I'm not sure why it isn't asking you for that, other than that it is still early in the tax season and there tends to be a lot of bugs and incomplete sections in the program. Personally, I would just wait another couple of weeks, but maybe someone else will come along with another suggestion.
If this isn't the first year it was placed in service, go back and look through the questions for the one that asks if you previously used the Standard Mileage Rate, and make sure you said no to that.
