I'm planning on marrying my cousin sister

My cousin is 15f and I'm 20. I love spending time with her ever since I knew her when she was little. She makes me feel loved and special. I love her face. But I'm a bit scared as in today's culture cousin marriage isnt really a thing, But I'm still willing to take the risk, I think she is worth it. As she is at a young age I dont think its appropriate for me to directly confess to her. I wanna send the marriage proposal via my parents. My aunt really compliments me a lot. I'm pretty confused on how to do this any advice would be great.