IIN being nude in front of your 20yo younger sister?

When I was young I accidentally noticed my older brother changing his underpants in front of his bed, I was just walking thru the hall and he didn't hear me nor see me, after that day I started to think about him a lot. When our parents went out to attend a party it was just me and my brother in the house and I just felt to spend more time around him. We were watching a scary movie and it wasn't scary for me but I asked him to give me a hug so I could be closer to him. And I asked him to give me some ice cream and he said no at first then I said please three times and he agreed. Then I smiled but not for ice cream it was because I wanted to annoy and tease him very much, lol. It was the first time I noticed how strong, smart, and brave he was and how much I trusted, respected, and loved him. Later he was sleeping in the sofa and I carefully touched his pants because I was so curious. But he never found out anything. And when I was teenage I had a boyfriend but I always compared him to my older brother, not just in personality and character but also how much he could give me the similar feeling of excitement which I got as a little girl when I was lucky enough to see my brother fully naked. I know it was wrong to have feeling for a family member but I couldn't stop the thoughts and because society says no it is very bad this is why in my mind I felt it so strong desire, and it was also the first time when I had seen a man in such way <3 ALso, it was my secret to see my brother naked and he didn't know so I felt very bad but in a good way :)