We spend our whole lives trying to figure this out, kids, adults, all of us! I love the advice the others provided here, and I would also add that there is no need to "know" yourself. You are an ever changing and evolving being and do not need to know everything about yourself. When we spend time putting ourselves in a box and calling it "me," we forget to continue to learn about ourselves. Every day, I can surprise myself with my strength and courage and other days, I'm the most afraid person I've ever seen! But, all of it is "me" and it doesn't mean anything at all.
I think the most honest input I can provide here is to spend time watching yourself, your reactions, the people you tend to gravitate toward, the decisions you make. I found incredible help through some tools I've listed below for you, as well. I find that silence can be an incredible helper in slowing down and seeing yourself more clearly. The best thing I've learned is to be open to myself and patient. I'm never going to know myself 100% and that is part of the journey of life. :) Enjoy it!
www.thework.com by Byron Katie
https://ejlavine.com/ by Elizabeth Lavine