Welp, when I was still living at home, my parents did pay for a lot of my showing expenses. However, they limited the number of shows they would pay for and then I was responsible for the rest.
Since your parents are lending you the money, my personal advice would be to limit the number of expenses (shows) you incur so that you can a) have hope of paying them back in a short time frame and b) once they are paid back, you can start socking away money if showing is something you absolutely are dead set on doing.
And it might be nice to tag along with your stable - even if not to show, but just to help, etc.
Your mare is really pretty - love her colour. She's very similar in colouring to my mare.
What do you plan on showing her in?