Am I Shy?

I don't know why. I don't understand what brings it on, but somedays I just want to write. I'll go weeks without anything in particular to say and then all of a sudden I have days where I just want to keep adding stuff. Today is one of those days.
When the whole family was here in June for our reunion, all of us girls went to dinner for Carmen's birthday. That night I realized something that I hadn't really thought through before. We were all standing outside Mai Thai talking...amazing enough in itself since we'd already been inside for 3 hours :) Yes, we have dinners like Italians, they go on forever! Anyways, Jenae & Kathy were talking about grandma. Jenae mentioned how she had noticed that she was much quiter this weekend and kind of reserved, staying in the shadows. And observed that grandma tends to be like that whenever Mary Ellen is around...as if, when they were growing up grandma would be in the background and Mary Ellen would take over. So now even though they're older, whenever the 2 are together grandma reverts to those old ways and lets Mary Ellen take charge. It makes perfect sense. I never thought about it before, but I am exactly the same way.
As long as I can remember my parents & sister have thought of me as shy. I have always been the shy, timid one in the family. And my sister still thinks of me like that. What's funny is that my friends here thinks she's crazy. They do not see me as shy, not at all.
I am a totally different person when I'm with my friends here, friends that do not know my sister, have never spent real time with the two of us in the same place. Yet, even now, after 3 years of living away from my sister...when I'm back in that situation I revert back to that behavior. Not so much on purpose, it just seems to happen. When I'm with Jaclyn I become a quieter, more reserved person. I guess I become the shy person that she believes I am. even though I don't think of myself like that. It's not a bad thing, it just is. She is loud, she LOVES to talk, she talks to EVERYONE, she enjoys talking about people, talking about random topics, did I mention she LOVES to talk? And when we're together, SHE talks. I listen. I don't like to talk, at least not all the time...typically only when I have something purposeful to say. I definitely don't enjoy talking to everyone, I would much rather only talk to people that I care about. I hate talking about people...people that I never see and don't know, I don't like to talk about or to people just to talk. I like to have a reason to talk. So, when I'm with Jac she talks. I listen. And it works...its how life has always been. It's just weird to me that I can be so different with her then with the rest of the world. Seriously, all of my friends laugh when my sister calls me shy. Sometimes I wonder if that's healthy. Is it normal to be different with one person then with everyone else? Am I being true to who I am? Or am I simply doing what's easy? Does it really matter? All those years growing up...was I a different person? Was the real me just waiting inside, waiting to get out? Or have I changed that much? I don't know. I don't understand. I don't want to be 2 different people. I want to be who I am. All the time. Whomever I'm with...but maybe I will always be a little more on the shy side when I'm with Jaclyn. And maybe that's okay.