Hi Christie,
When a guy and girl get shy only around each other, it often means that they are attracted to each other but have insecurities about how to go about approaching each other.
He has most likely been doing exactly what you have been doing, overthinking.
He worries about being awkward in his approach or not being able to carry on an interesting conversation.
The both of you are extroverts and probably have a lot of commonalities in how you both approach life and in the way you both think.
Unfortunately, being that the both of you are so similar in a number of aspects, you’re both allowing yourselves to get too caught up in what the other person will think about them if they were to make a move.
In order not to put yourselves in a position of possible embarrassment, you have both unconsciously chosen to put the onus on the other person to make the first move.
That is why the both of you are currently stuck stealing glances at each other and nothing more.