Introversion as a result of motherhood? Or aging? Or busyness? Or medication?

When I was younger, I definitely skewed more extroverted.  I felt like I needed to be around other people for energy, in order to thrive.  I was neither comfortable nor happy when I was alone.  I didn't know what to do with myself if I was by myself for very long at all.

D told me tonight that I have become an introvert, which I found surprising, not because I hadn't thought it but because it is obvious enough for someone else to notice.  I tire of people so easily now and really welcome nothing but silence when I have moments to myself.  By the end of the day, I find myself saying, "I really need for you to stop talking to me," to both D and the kids.  My ears simply can't listen anymore.

I'm not certain whether this introversion is a function of motherhood.  Perhaps being with one or more of my children for all but 9 hours of the week for over a decade will do that to a person?  Perhaps because I am being talked to I am simply worn to a sensory nub and require quiet to decompress and revitalize for more chatter the next day?  

Or maybe it is a function of having a busy life?  Because of the kids I feel like I am always running errands or planning something or taking someone somewhere, so I relish any time I get at home, inside, where I am not around tons of other people.  

Or maybe it is a function of being medicated and having my thoughts not drive me crazy?  Maybe having a quieter, less worried mind has made it easier and more pleasant for me to spend time with only myself?

Or maybe this is just what happens as a person gets older?  

Or maybe it is a function of being married to an introvert for 17 years and picking up habits?

Some time ago, I took a Myers-Briggs test and was smack dab in the middle between extroversion and introversion.  Perhaps how much I lean toward introversion changes depending on how much people/chatter time I've had?  

I think because I like to chat with people and am pretty approachable and friendly, people automatically put me in the extroversion category and might be surprised by the notion that I'm moving more towards introversion.  

But introversion doesn't mean a person doesn't like to talk;  I'm not shy; I just find that talking too long....or being talked to too long....sucks my energy; wears me out.  Makes me feel like I need to go away and recharge with silence.