I was a senior in high school and I was planning to go off to college in the fall. My sister was a sophomore -- two years younger than me. She may have only been 15 years old, but Jane was quite a beauty and I thought she was a knockout even though she was my younger sister. We had an even younger sister, Stephanie, but she was only in the sixth grade and didn't factor into what I'm going to share with you now.

I'm actually not sure what size bra Jane was wearing when I really became aware of how she was developing into a young woman. Yeah, she'd started her period when she was about 10 or 11 years old and all the normal things that happen to a young girl in puberty began to happen about then too. By the time she and I had the experience I'm going to relate, she was very well developed physically along the path to becoming a woman. I helped her along that path.

I'd had sex with several other girls my own age or within a year or two of my age. I had one girlfriend my junior year who was actually a freshman in college but we'd known each other in school before she'd graduated and gone off to school about 100 miles away. She came home one summer and we'd started dating and then our relationship became intimate and we enjoyed fucking each other all summer long before she returned to school and then she found some other guys there to keep her sexually happy.

The interesting thing growing up in a house with a younger sister or two is that you just naturally get to watch them start to mature physically and while it happens slowly, day after day, you'll eventually start to notice that your sister's got tits, she started to develop womanly curves and if you're really lucky, you might even catch a glimpse of your sister's pussy or her breasts and nipples as they begin to grow on her chest. I had all those experiences with Jane and looking back now, I'm not sure that many of them weren't very intentional on her part to seduce me or at least to get my attention sexually.

Anyway, Jane was very cute and I had increasingly thought she was very sexy from when she was in 8th grade on. She was probably wearing at least a B-cup bra in 8th grade and by her sophomore year in high school, she had serious B-cup tits or maybe even starting into a C-cup. I just know this -- Jane could fill out any top or sweatshirt or blouse she wore. She had a nice chest. It often gave me hardons as I'd watch her prancing around the house or playing around outside.

Our mom had passed away when I was in 6th grade so the three of us kids had grown up with Dad and we were all very happy and secure. He did a decent job of taking care of us, he worked hard, and he could cook a decent meal for us kids. Early on, Jane and then Stephanie also learned how to cook so we all made it along OK.

All though my senior year of high school, I'd been dating a girl who was a year younger than me named Becky. She was pretty and I loved being with her and having her with me but we'd never really been serious or thinking too much about the future. We just enjoyed doing things together and eventually we started to make out and then moved on to her sucking my cock and us fucking together. Becky was very sexy. I hadn't been the first guy to fuck her and I'm not sure who got her cherry, but we both enjoyed making love in her bedroom, in my bedroom, and in the backseat of my dad's car when he'd let me borrow it for a date.

It was April of my senior year and I'd come home at about 10:00 P.M. from a late evening at the grocery store where I'd been working for almost two years. I was sort of tired and had a little bit of late semester homework to do before I showered and hit the bed for the night. I had noticed throughout the late afternoon and evening that I was feeling more than usually horny. It had only been a couple of days since Becky and I had enjoyed a fuck together. Sure, sometimes we'd get together after school or in the evenings and we'd fuck nearly every day, but both of us had been more than usually busy and we just hadn't gotten it on for a couple of days.

I'd gone to my room and settled down to do the reading and writing I needed to get done, when there was a slight knock at my door and my sister Jane stuck her head in to see what I was doing and then she came on in and plopped herself down on the end of my bed. Jane and I were very close as a brother and sister and she'd often come and bare her soul with me when she was having boyfriend or Dad problems -- or even problems at school with a teacher or with one of her classes. I didn't mind her coming in but I hoped to myself that she wouldn't stay too long so I could get on with what I needed to get accomplished.

When Jane came into my room, what she had on caught my attention like nothing I'd ever seen her in before. Jane had put on a sexy little yellow babydoll pajama outfit and I was almost instantly embarassed to realize that as I looked up and saw Jane, my cock started hardening in my briefs. I'd stripped down to just my briefs and T-shirt and was sitting in only those items as I'd sat there reading. I moved slightly and sort of let my book lower down over my crotch so Jane couldn't see the big hardon that was growing there in my briefs. What was I doing getting a huge hard cock from my younger sister walking into my bedroom?? Yeah, I'd had sexy thoughts about Jane before, but I didn't want her to know it. I'd even fantasized about having sex with Jane and I'd jacked off on more than one occasion with images of Jane in just a bedroom outfit like this, but I'd never envisioned that I'd be confronted with her sitting on my bed in a babydoll.

The sexy thing about seeing Jane was that she either didn't realize how sexy and provocative she was wearing that in front of me or she was doing a good job of concealing how she thought she appeared. I didn't know which. Jane obviously was naked under the babydoll and there were her sexy breasts poking out against the material of her nighty. Her nipples were dark brown and and I could clearly see them through the top of her PJs. And it didn't appear that she had the babydoll panties on that went with that outfit at all. She was naked below the waist under her nightgown. Oh man, what a hottie I had sitting there in front of me -- even if she was my own sister.

As we sat talking, Jane would shift and move around and as she did it was as though she was trying to show me her tits, and her cleavage and then she turned once so I could clearly see up the underneath of her nightgown and there was her blonde-furred pussy in all its sexy glory. I could see the lips of Jane's 15-year old cunt and it even looked like her pussy lips were already wet and swollen from her being turned on. I thought I was seeing things. I didn't know if Jane was being totally innocent or if she was trying to seduce me but suddenly I couldn't think about anything else but my sexy teenaged sister with the body of a developing woman sitting there nearly naked in front of me.