I agree with Twig.
Recorder is very easy to play from a young age. DTDs have just started at 6 (15min a week at school + 10mins (supposedly) a day at home and they love it.
It is a good introduction to music, to learn what the symbols etc. mean.
Choice of violin or something else (I can't remember what) are offer her in year 3 - so they will move on from recorder. But recorder is very good for learning about the mechanics of music.
Do you have any experience of recorder playing?
DTDs have brought a book called PLaytime 2. This tells you all the notes and moves in a logical way through - such that I could easily teach them if I wanted to. I did a bit of recorder at school (didn't start until equivalent of year 6)