Children's Bikes....what size??

Summer is definitely here and we're trying to squeeze every second out of these long warm evenings!! Getting started we pull the little ones bike out from the back room and she jumps on. What has happened........she was only on it a few weeks ago? ...maybe it was a bit longer?.......her legs seem so long.....can we just raise the saddle a bit?....

Yes kids grow fast and there were a few things we tried to get a few more weeks out this bike. After raising the saddle, moving it back raise and extending the stem we gave up and got a 24 inch wheel FROG frame. For an age 9 average height girl, it's great. Works really well for mountain biking (with off road tyres and a little softer for shock absorption) and on road/track!! till next year anyway!