D00d, if your granddaughter's experience is going to be anythnig like my nieces you and the bike will be a huge hit. My niece turns three in February and she ended up having to have two of these things. One for her house and one for my mom's place so that when she spends days at Grandma's she can ride in the big yard there. She just loves the silly things.
She got here first one at just about he same age your little one is getting hers now. So if that comparison is at all valid you'll get some good entertainment out of watching her learn to use the foot control. You might also not want to hook up the high gear switch for the first couple of months. Low gear is a comfortable walking pace. High gear she will outrun you. And until the hand to foot coordination comes in a little better low gear turned out to be a good option.
Once it all clicks in her little head though she'll be big stuff on wheels. And look out for anything in their way !! [smiley=xyxthumbs.gif]