You don't need any application of the throttle pedal to get the car to move forward. Especially at initial start up when the car is still in high idle. Pulling out of my garage, I don't touch the throttle pedal until I get to the street and put the car into 1st. The driveway is sloped, but the garage is flat.
You can also use first gear when the car is rolling, you just have to rev match so you don't get the huge jerk when you engage the clutch.