Cycle feelings or do I have a good reason?

I feel upset about this and I am not sure if I am been dramatic.

I am 20 y/o and my sister is 16 y/o, since the beginning of the year I have been telling my mom that I would like to use her car to practice driving, I already have my license but since I got it I hadn't have the chance to go out and prove myself. Her answer have never been positive "I don't you to crash my car", "I don't have money to fix it if you crash it", "do you have money to fix it if you crash it?" and so on... all things that make me feel so insecure.

But.. what do I see? She lets my younger sister drive it u.u She now says I don't the time to practice (which is part true, I work long hours) but when I do have the free time she always has an excuse.

I am not jealous but I do feel mad that she doesn't trust me, that she doesn't make me feel confidence like I know I made her feel when SHE (my mom) was learning how to drive a couple of years ago.. in my defense I DO WORK, I have to money to pay for it if I crash it, my sister doesn't.

So I told her, quietly and very nicely, that I was mad about it and she laughed.

Why do I feel I could be overreacting? Because driving isn't even that important to me.. I prefer to use public transportation and not planning to get a car but either way.. I am not happy.

(Sorry if typos)