Re: Introducing Sippy Cup...
Not too young at all. All my 3 kids started at about 4 months old. If you just introduced it then it is your baby is still figuring it out. I started early to give my babies a long time to figure it out.
My 9 month old can now drink out of different types of sippy cups, some better than others. He still spits out water when he doesn't want it. It is like he is playing with it.
I would second ont he suggestion of trying different ones, some kids like certain types better. I would get some with straws, some with a silicone tip and some with a hard tip.