The impossible quest for grown up friends

My sister's BFF posted this clip from Seinfeld on her facebook recently, and it inspired me to write this post.  It fit perfectly how I feel.  See, I have some "best friends" (which reminds me, I do believe that "best friend" is not a title held just by one person)...but they live thousands of miles away. (Maybe. I'm not good with distance/geography.)  They also are friends I made as a 4 year old, and a very young adult.  What makes young adult different than now? A lot. I was single, I had no kids, and I was still (relatively) cool.  Of course the friend circa 1986 was the easiest friend I ever made.  We had stuff in common: we were friends. *see video clip, if you didn't watch it.  By the way, why didn't you?
So, here I am now, 30.  I am married, with kids, and I'm a stay at home mom.  I feel like all those things are negatives against me, at least in the 'making friends' area.  Some people would think "oh, that's not true! Make friends with the parents of your kids' friends!"  Uh, have you tried that?  I mean its awesome when that works. For reals.  But I take Sophie to dance class and just...no.  And you know, there are probably lots of other moms that feel this way but we don't have an identification system worked out, so how do you know who feels the same as you, and who is just rolling in the friends and as happy as can be, and has no room for any other friends?  HOW DO YOU KNOW?  When I was younger that wasn't something I ever thought about.  I don't know why its the deal now.  But it so is! I have some acquaintances, some casual friends...but I miss having those friends who are so close that you know everything about each other, and you can be *real*.  Friends who will just come over whenever they want and walk into my house like they live here because that's how close we are.  Its been a long time since I had that and I miss it dearly.  My BFF/roommate from my early 20s and I did everything together.  We talked about everything, we knew everything each other was feeling.  But now we live states apart and we both are lame and have husbands and kids so...womp womp.  I like to think that if she lived down the street things would be the same as they used to be.  My best friend from childhood and I still talk nearly every day thanks to the wonder that is facebook, and I am so grateful for that.  That's 26 years of friendship!  You don't get that often.
But how do you just learn to be real with friends at this age?  How do you allow yourself to go from acquaintance to REAL FRIEND?  I do not know the answer and it seems as if its some sort of riddle.  I don't think I know how to let my guard down.  There's this thing with appearances, etc., that I get hung up on.  I'm not sure exactly how to explain it.  But I didn't feel it when I was younger.  Do they want you to be a surface friend?  In my head, the answer is yes. In my head, everyone already has their "close friend" quota and I'm not needed.
Whine whine.  Its hard! I'm glad at least that Jerry Seinfeld sorta knows how i feel.  A little.