I'm looking back through other threads suggesting sippy cups and wondering if there's a particular type/brand that would be good for a younger baby (4.5 months), or if she would even be able to figure out the sippy at all.
We used sippys fairly early because J wasn't a bottle fan. We used the tommee tippee soft spout ones. He really took to them. They have handles so it was easy for him to hold them.
DD prefers a straw to a sippy because all she has to do is suck. She's a do-it-yourself girl though (prefers to feed herself rather than me spoonfeeding).
I think we introduced it right around 6 months and she got the hang of it right away. She can now grab and hold it all on her own. We always keep one in the diaper bag for when we're out and about but the nice thing is that since it's a straw type, if we happen to forget the cup it's not a big deal as she can just drink water from a regular straw!
I introduced a sippy at 4 months because my kid wasn't great with bottles. Pedi wanted a straw, so I got Zoli cups. Took him about a month-month and a half to master it, but it was hilarious to see a bitty baby sipping from a straw cup. Haha.