You should be fine. Until then, you have some time to figure out how to calculate Earth's distance from the sun using the Venus transit. Dot Physics blogger Rhett Allain provides a walk-through.

Learn the difference between distance, displacement, speed and velocity, and how to calculate distance, speed and acceleration.

Speed is a measure of how fast an object is moving. Calculate speed using the speed equation - speed = distance divided by time. The speed equation can be rearranged to find distance travelled and ...

The energy/time uncertainty relation means that the uncertainties become larger than the things we know how to calculate. In short, physics as-we-know-it doesn't work anymore.