Even though you may be hesitant, you should always inform your insurance company about an accident, no matter how minor, to see how it will affect your rates. It’s better to find out of any increases now than see a hefty renewal down the line!
As for increases, if you weren’t at fault for the accident, and it was your first one, then your premium may not increase very much. If you were at-fault for the accident, you will probably lose any good driving discounts associated with your premium. You should also expect your yearly premium to increase by as much as 25% for the three years.