You have asked your question in the Hepatitis C community forum.
Hepatitis C is not generally considered to be an STD although there is a small risk of sexual transmission.
In order to transmit hepatitis C blood from someone who is infected with the hepatitis C virus must enter the blood stream of a person who is not infected with hepatitis C.
This would require the person infected to have a fresh open actively bleeding injury and then that blood would have to enter the blood stream of an uninfected person.
The most common method of transmission is the sharing of IV injection needles or having a blood transfusion prior to 1990.
Less than 4% or the people in the US are infected with hepc so the likelyhood of randomly encountering someone especially a young girl infected with hep c is very low. The odds of contracting hep c in this situation are bordering on impossible.
For other blood borne illnesses you could ask in the appropriate forum. You could also look in the CDC web site by searching for the illness you are concerned about or better still ask your doctor.
But in general from what you have described the possibility of transmission of anything is nil.
I see you have posted similar questions in the past. Have you considered speaking with a counselor about anxiety for your concerns about blood and illness transmission?