First Sign at 5.5 mos!

Hi all,
My son has just signed his first word-milk! The sign for milk is an opening and closing of the fist. He was looking at his hands and then he put up his arm straight in the air and then open and closed his fist twice and then brought it back down and then carried on looking at his hands and then sucking on them. He has done this now a few times. It looks very purposeful as he becomes quiet and still, performs the sign and then resumes his activity. The sign MILK is the most frequently used sign that I use with him in the day and perhaps one of the easier hand movements to perform.
I have this on videotape too!!! It will be nice to show him his first word when he is older!

Anyone else have a similar experience??

Natasha