day 16 - i'm growing up so fast

Today I was reading a booklet on child development. It was quite interesting and it seems Jarrett is doing a lot of the things he should be doing at 14, 18+ months (well, except for the walking part). Interestingly enough it said at 12 months the child should be walking holding onto furniture and it's not till 14 monhts that walking alone is listed as a milestone. According to what I was reading saying mama and dada specifically is at 14 months and he's been doing that for about 2 months now, he knows dada more than mama (not sure why). At 18 months, it says he should use 3-5 words other than dada, he does that now with bubble, hi, bye bye and doggy. At 18 months, it says he should drink from a cup, he does that now and has been doing that for a while too. At 24 months it says he should walk upstairs, ok, I'm really pushing here but what is the true definition of walking? Is it putting one foot ahead of the other? If so, Jarrett does that now too! :)