Benjamin Button-itis

I've noticed in my life that the older I get the younger people think I am. (Not a bad deal) My whole life people always thought I was older (sometimes much MUCH older) than I actually was. These are a few examples, some are pretty extreme and will seem untrue, but I tell you now, everything you are about to read is 100% true.
Age 12 I was at Academy for Girls (EFY but for the younger ages) we went to an old folk's home and I was helping and elderly lady make a hanger for her doorknob, and she said to me something along the lines of, "Things are so difficult once you get to my age, it's so nice to have you young people come and help... how old are you? 20? 30?" This is where it all started.
When I was 16 I sang at my cousin Shad's wedding. My cousin Marissa was there with her daughters. Her daughter Kierra was 6 months old. I LOVED holding her all the time. At the wedding Kierra was sleeping in my arms and this lady came up to me, and said how beautiful she was, followed by, "That is such a bonding time for mother and child, when they sleep in your arms." I didn't want to embarrass her so I just said, "Yeah..."
Next example: When I was 17, a senior in high school. I was taking a class called Elementary tutoring. I was planning on being a teacher and in this class I would go to an Elementary school and basically was an aid in the 2nd grade class. Toward the end of the school year they were doing a talent show. At this point I had bonded with the kids and they really wanted me to go. So I went and sat amongst the parents. One lady turned to me and said, "Which one is yours?" I just looked at her in shock and said, "I'm 17! I'm the aid for this class." Really lady did I look old enough to have an 8 year old?
That same year(this is where it starts to get crazy) My sister was cheering for the University of Utah. I drove her to her practice in the morning and they had some sort of orientation so I stayed to watch. At the end of the practice Jennie came up to me. Keep in mind she was 19 at the time, and again, I was 17. We talked for a bit and then she walked away, and this older lady came up to me and said, "Are you the mom?" SERIOUSLY!!!! I looked at her in SUCH disgust and said, "I'm her YOUNGER sister!!!" to which she replied. "Well that's nice." I was pretty upset... I get that I look older than I am, but old enough to have a 19 year old daughter???
A few years later I was talking to an RS president in my single's ward. She asked me how old I was and I said, "21" she was shocked and said, "Really I thought you were my age." I remember being totally appalled at that as she was 27 (I think about that all the time now as I am now 27... do 21 year olds still think 27 is SO OLD???).
A couple years later. I was at work and it was my birthday. This guy who came into my office somewhat regularly said, "So how old are you... 24... 25?" I said, "Oh I'm 23.." Smile turned to shock on his face. "Oh... I was kidding... I thought you were... older." It was then that I realized he was trying to be flattering by obviously guessing way younger than he thought I actually was.
And finally. The story to end all. When I was 21 my sister and I were at a restaurant. I was holding her 6 month old son Jace. A lady (obviously old and senile) came to us and said how cute he was and asked who the mother was. I pointed at Jennie and just smiled. Then she looked at me and said, "And you're the grandma?" Right away, Jennie nearly choked on her laughter. I just looked at her and said, "No"
As I said though, the older I get the younger people think I am now. Someone guessed yesterday that I was 20-21, according to these stories the last time I would have looked that age would have been like 10. I have some ideas as to why, but the drastic-ousity of the guesses still surprise me.