DD frightened of the potty, her small bum fell in! What now? A potty chair?

[HowNowKernow]

My DD is 2.5yrs and is small for her age, only 2nd centile on the charts. She is ready to potty train I think, telling me if she is going to do something and then asking me to change her nappy afterwards She was even asking to use the toilet like mummy does, but when we bought a potty, a regular basic one, she tried to sit on it and pretty much fell in.
Its massive for her!

Would I be better off with a potty chair like this? www.argos.co.uk/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&catalogId=1500002901&langId=-1&productId=1501065651 Then she could feel a little more secure?

Or should I just wait and try again with the basic potty?

[BertieBotts]

You can buy smaller potties. The baby bjorn little potty is tiny - about the size for your average one year old.