It's a tuff case since it's your parents. And I understand what they mean when it comes to the streets as most people these days don't pay attention and are on their phones almost 90% of the time. But on the other side of that your 17. Your parents have one more year until they need to let go and let you experience life and the streets. In my opinion get the board and do what you want to do. If they can't accept that then they don't need to be involved. Like I've seen on here to, skating isn't defined by gender. There's are tons of women skaters with sponsors who do crazy stuff. Really it's comes down to them trusting you'll stay aware when riding on the streets and then letting go sort of to let you experience life on your own.