Spying on Rosie

My name is Charlie, and this is the story of how I spied on my girlfriends little sister, Rosie.
We lived in a three bedroom house in the country. Just me, my girlfriend and her mom and sister.
We lived in california and it was always hot. Usually in the 80's or 90's.
And Rosie would usually just walk around in tiny short shorts and loose little tank tops. Revealing her long beautiful legs and and decent amount of her tight little booty. She had dark brown hair and eyes, which were big, brown and incredibly sexy.
I couldn't help but notice when she walked around. I tried not to let anyone see me looking so I had to be carful not to be caught.
My girlfriend Susie and I shared a bedroom on the bottom floor, it had its own door to the back porch, Rosie's bedroom was right next to ours with her own door to the back porch. Since we lived out in the country she had to wake up early in the morning to catch her bus. So her alarm clock would wake me up every morning at 5 am. At first I just laid in bed trying to fall back asleep. After like two months of waking up every morning I decided to start having breakfast with her. She walked out of her room and walked into the kitchen wearing a robe and a very sleeping expression on her face. "Morning" I grumbled to her. "Mmmmpphg" she replies. I pour my self a bowl of cereal and left a bowl out for her. She poured her self a bowl and I couldn't help but look at her legs which were mostly showing because her robe was kinda short. As she put the cereal away on the top shelf in the pantry she stood on her tippy toes and reached high. Raising her robe and revealing half her naked ass. It was so small and tight, I couldn't look away, finally she came to sit down and eat at the table with me. I'm sitting as close as I can hiding my stiffening cock in my loose pajama pant's. We just ate in silence, she just stares at her bowl and eats slowly. I, however was looking down her robe which had opened and was revealing part of her budding breast and just a little bit of a pink areole. My eyes where stuck. I only looked away long enough to make sure she didn't see me. She finished her bowl and got up and said "later" in a sleepy voice and walked into the bathroom and closed and locked the door. Five minutes later I hear the shower turn on, explaining the being naked under her robe. I just sat there and left my hard on calm down, shocked at what I had seen. When I finally calmed down I just sat on the couch and read a book. At about 5:40 she is out of the shower and walks to her room wrapped in a towel tucked under her armpits. Her hair wet and sticking to her back. She smiles at me as she shuts her door. I am lounging on the couch reading still when she walks out around 6:00 asking me if I liked her shirt outfit. I look up and she is wearing tight leggings and daisy duke shorts and a tight little purple t-shirt that just wrapped around her little baby titties perfectly. "Uh, sure." I replied simply but thinking "I want to just take them off little girl." She picked up her backpack and went to school. I sat there thinking about what I had seen that day and was just mesmerized. She had such a sexy little body. I snuck into her room and opened the blinds to her window a little bit at the bottom. And then went down the hall way and opened the blinds to the bathroom window and then got dressed and did some yard work while Susie went to college and Julie (Susie and Rosie's mom) went to work. I just worked and waited. I had to see more, it was like I was exposed to a new drug. When Rosie got home she ate a snack and did her homework. Susie and Julie were home. They were making dinner and I was enjoying a beer and smoking a bowl "watching tv" in reality I was keeping my eyes on Rosie who was sitting at the table. After a while she got up and went to her room. I got up and went to mine and sneaked out the back and went to her window. I crouched down to peek into the crack in the blinds I made just in time to see her take her little bra off. I was instantly hard. Her little tits where so perky, her nipples where pink and the size of dimes.
She then took her shorts and leggings off and turned toward her closet with her back to me in just white cotton panties. She grabbed another pair of short shorts and a tank top and pulled her panties off and I marveled at her tight little butt. It was begging to fill out and had a nice roundness to it. I slipped one hand in my pants and started to stroke myself slowly. She bent over and put her shorts on exposing her little pussy with just a sprinkle of brown hair on it. I stroked myself a little faster. She pulled on her tank top, turned off her light and left her room. I moved away from her window and pulled out my throbbing cock and stroked myself off to orgasm and came hard off the back deck. I cleaned myself off with a leaf and started to think about what I had just done. Feeling sick for spying and jerking off while watching Rosie change, but also not really caring either……