Dd is 4 in a few weeks and I'd like to get her a scooter. She already has a 3-wheel scooter with the Tweenies on it, which she loves using, but it's a bit cumbersome and slow. I'd like to get her something a bit more grown up, but there seems to be so much choice and I don't know where to start. 2-wheel or 3-wheel, mini micro, folding, plastic or metal. Any advice please on what is likely to be a good investment that she'll enjoy using for some time to come. Thanks!