Where did my baby go?

Putting Ethan to bed last night, I realized how big he is getting.  He is not my baby anymore, that is for sure.  He started the finger wag yesterday.  I always wag my finger at him when I say "no no".  I wag it a something that he falls and hurts himself on when I say "bad" (such as "bad wall", or "bad Marley").  He now imitates me. Telling ME "no" is right around the corner for him, I am sure.  He also tried to crawl out of his crib last night as he was going to bed.  Way too small for that,yet.  But again,just around the corner.  And now when he knows he is doing something wrong, he will look at me and smile.  When I say "no no" again, he laughs.  When I swat his little hand (okay, I barely touch him,but it is the thought that counts. Right?!?!) he laughs HARDER.  He thinks it is a game.  I try to keep a straight face.  I really do.  I definitely need to work on my discipline skills here soon.  I don't want one of "those" babies.  And he has some definite "those baby" potential right now.  The way he throws a tantrum at even the thought of not getting his way. Oy Vay!  I am sure I will figure it out. Hopefully sooner rather than later.  Because he is asserting himself more and more every day.  I am not sure where that comes from. . .