I got my drivers license but my mom won't let me drive?

[It's Kat Darling!]

I passed my drivers test the first time. The only thing the guy said I needed to work on was confidence, which I will get as I drive more. The only reason I wasn't the most confident was because my parents car was making really weird noises and felt weird. It hadn't been working earlier that day, and it died the next day. So now my mom is convinced I need more practice for confidence or something..

She makes me go 55 on a 70mph speed limit freeway. She SCREAMS at me when I miss a turn or ask a question. She only lets me drive around the block by myself.
I HAVE my license. I am a SAFE driver! What can I do to convince her? Driving doesn't help because apparently, when I go 60mph on that 70mph freeway I am putting everyones life in danger. She doesn't even want me to drive to my own job by myself! -.-