Opportunity Cost

For some reason, I thought it would be fun to browse back through some old yearbooks of mine.  It was fun, but it made me very nostalgic.  I had a blast in high school, and miss it a lot.  I am guessing a big reason that I miss it so much is because I went to high school in Colombia, and haven't been back since I graduated, nor do I have any immediate plans for a trip in that direction.  (And I LOVED Colombia.  If I could be Colombian, I would.)  Many of my friend are more nostalgic for college, but I prefer high school.  The main reason is that in high school, I could dream big.  By the time I was in college, I had to make decisions about my future, not just dream about it like I could before. 
In  my senior yearbook, each senior had a whole page to write wills or dedications.  Many of the people who mentioned me in theirs mentioned Physics or Chemistry (or Math).  I was quite good at those subjects.  I think most people who know me now would be surprised.  I also won a Calculus award my senior year.  Yes, I am apparently a math and science geek.  I was also going to be a doctor.  I wanted to be a pediatric oncologist.  Obviously, I didn't end up doing that! 
Now, I have no regrets.  I do enjoy my life, but sometimes I wonder.  In my Economics classes in college, I learned about opportunity cost.  That basically means that by choosing one thing, you are giving up many other options (those other options are the opportunity cost).  I have been thinking about my Opportunity Costs today.  What I had to give up to get here.  Many may think that I didn't have to give anything up, that I could have had it all.  But I disagree.  To be the kind of mother I wanted (and still want) to be, there is no way I could have done medical school, and held down a job after my kids were born.  There are some days when I feel like I need to be so much more, that my brain is atrophying away by spending hours upon hours relating to young kids.  Those are the days that I wish I had done more to have a career.  But then I comes back to my children, and how even imagining someone else taking care of them makes me hyperventilate.  In time, when both kids are in school full time, I do hope to go back to school to get some sort of medical degree (probably some kind of nurse) and I hope that I will make the time, and have the money to do just that. 
Does anyone else feel that there is a whole other person inside your "mom" exterior?  I am trying to find a way to bring these 2 people together, but so much of my day is "mom" that this other person (who I think is still in high school, because I don't feel a day over 17) gets ignored.  Any ideas on how to bring these 2 people together, or am I the only one who feels this way?