It seems to me that this song is about finding love again later in life and feeling the excitement of being in love again. He says he is acting like he is 21 again, just completely awed by this new love. Back at square one, feeling dumb. He fumbles to know what to say, what to do, so as not to ruin this feeling. He sees this girl everywhere, completely consumed with her, not obsessed, but feeling alive and feeling scared. He refers to this girl as lightning, as if to say, your brightness scares me like a child, but its an exciting fear.
It seems to me that this song is about finding love again later in life and feeling the excitement of being in love again. He says he is acting like he is 21 again, just completely awed by this new love. Back at square one, feeling dumb. He fumbles to know what to say, what to do, so as not to ruin this feeling. He sees this girl everywhere, completely consumed with her, not obsessed, but feeling alive and feeling scared. He refers to this girl as lightning, as if to say, your brightness scares me like a child, but its an exciting fear.