baby sign language

Any one teaching their baby sign language? I started at 1 month with signing 'milk', 'more' & 'food'. At 4 months I started associating 'milk' with her bottle. Well last weekend she started signing it back!!! It's hard to catch, but she opens and closes her right hand and every time I give her bottle after she signs, she gobbles it down! This has been happening before her hunger whining even starts!! I wanna hear other mama's baby sign experiences!