My sister and i share a car?

ive gotten pulled over 3 times over two years, 2/3 when i was under 18, and once after. ive only gotten one written warnings the other two nothing. my sister recently got her license and has been driving the same car i do. she is 17 and got pulled over for speeding. she got a ticket of $100 for her first time getting pulled over. does this have anything to do with my warning since it was the same car, or does it go by individual