Am i wierd or is this normal

I just want to get some opinions. My sister is older than me by two years. Lately I've been noticing how pretty she can be at times. We were just on vacation in obx and were at the beach and in the pool everyday. She looked especially good in her bathing suit. I kept looking at her ass and pussy. One night we had a fire on the beach and she wore her sweatpants. when she was standing by the fire I could see that her pants were pulled tight and I could see the outline and split of her whole pussy. I got a major boner. All night her pants were pulled tight. I couldnt stop looking. I ended up jerking off to the thought of it that night.
We went to a lighthouse the next day and she wore tight jeans. I couldnt help but stare and get her walking on my camera phone. I keep jerking off to it. I know most won't do all that I did, but is it wrong to be atracted to her?