Sorry this is really late, I don't go on this account ever.
If you haven't set it already, just set it somewhere you think would be challenging. When I was 12 I did 10,000 words, the next year I aimed for 30,000 words. I skipped a year but when I was 15 I hit 40,000 words and then every year after that i've done the full 50,000. I picked something I thought was challenging every year. At the YWP stage it's a challenge against yourself. You want a goal that pushes you to work and grow and write a lot.
Hope that helps!