Boy do they grow up fast! My boy just used his super deluxe music-playing potty-sensing big boy potty for the first time today. Not once, but twice. Now the question is, which is worse, changing diapers, or hearing DAAAAD WIPE MY BUTT! There is no dignity in either one but one I am used to and the other is new.
Also, I read that you can get a good estimate of a child's adult height by measuring them at age 2. A boy will be 49.5% of his full height and a girl 52.5%. Having measured my boy he should reach about 5'10 or 5'11.