Today I discovered that my baby likes the sippy cup..

My babygirl will be 4 months next Thursday. She has been breastfed since she was born. I had made the mistake of not trying a bottle sooner so now she won't take any bottle and I tried a few different ones. Well today I bought her a sippy cup. Mostly because it was cheap and had one of her favorite characters (mini mouse) and I can't help but want to buy her everything!! Well we get home and she starts to get hungry so I thought maybe I'll just see what she does, so I pump. As I show the cup to her she showed excitement and actually started drinking from it. Of course she was throwing some out as alot was coming out at once but she drank more on it then any bottle before!! I tried again later in the day and she still really likes it and is starting to get the idea of how it works! So now I'm going to buy her better sippy cups and keep introducing breastmilk in it little at a time so she gets the hang on it. There isn't anything wrong with introducing the sippy cup this early right??