It is important to start the kid off in an environment that cultivates interest and musicality. Yamaha has the experience in years of teaching and their curriculum is pretty sound. Are you looking at putting your daughter in a one-to-one or group setting? At this age, if you're considering group, I'd say go for a smaller group whereby kids will get a bit more personal attention. Most important of all, a good teacher will be the make-or-break.
Whether to get a piano or not...that boils down to you. If you're putting your daughter in a group, then everyone's on a keyboard. In a way, it would be ok to just have a keyboard at home (but in the long run, if it's piano you want her to learn as oppose to electone, then better invest in a piano). If you're having one-to-one piano lessons then it's best to get a piano for her. You can start off with a 2ndhand which is less ex then slowly "upgrade" to better models as your daughter progresses.