Kourtney K with Kid 'They Get So Big, So Fast'

3/5/2013 7:33 AM PST BY TMZ STAFF
0304_kourtney_kardashian_SplashIt seems like only yesterday, Kourtney Kardashian was self-delivering baby Mason from her lady parts in front of the reality show cameras ... and look at him now!

No seriously, try to look at him ... bet you didn't even realize there was a child in this picture.