V1: A decision speed that Private Pilots can make use of too!
What is V1? Simply, it's a speed at which a rejected take-off procedure can safely be actioned and pretty much guarantee your aircraft stopping by the end of the runway. You do NOT make a decision at this speed, you make your decision well before you get in your aircraft.
What happens if I decide to reject the take-off due to some problem at a speed higher than V1? Chances are you won’t stop by the end of the runway and probably reach the proverbial 'dead mans curve' (too slow to take-off but too fast to stop). Another place you don’t want to find yourself.
V1 isn't a speed many Private Pilots are familiar with. It's usually associated with multi-engine passenger transport aircraft. That doesn't mean that you can't have one. Try this as a very good rule of thumb:
If you haven't reached HALF your take-off speed by a THIRD of the way down the runway, REJECT the take-off. Your controller/instructor will help you determine where the third marker point is on your runway. If not, google earth and measuring tools do a fine job.
One final point, please ensure you're all doing your fair share of rejected take-offs. They are not as easy as you might think when the aircraft is close to flying speed. As a student, you should have done at least 3 before going solo.