There were lots of bikes to choose from but we went with this Disney Frozen bike because she loves her some Anna and Elsa! In addition to the bike I wanted to make sure she had a seat for her baby to ride along with her, so I ordered this one from Amazon.
She practiced a bit the day she got it but didn't really get the hang of it until the afternoon that I let her ride it all the way down to the pool. A combination of going downhill and tons of help got us down to the pool and she's been confident on it since. Go, Kota go!