Thanks for posting. On the BeyondBlue website we have a checklist called the K10 which goes through some symptoms of depression. It's a helpful tool to start with, in order to get a rough idea of where you're at.
(Copy and Paste link) https://www.beyondblue.org.au/the-facts/anxiety-and-depression-checklist-k10
Headspace also has a page with some helpful information for you to check out if you want.
I understand that telling your parents can be scary, especially if you don't really know what's happening for you at the moment, but I always do encourage telling someone, even a friend, a teacher, or a school counsellor. It's important to have a support network who can help you and encourage you too.
Feel free to check in with us if you need a bit more info.