Hi there
I would recommend trademe if second hand is ok with you. Just check measurements before you commit as bike gear sizing has no rhyme or reason between brands.
I'm 5"2.5 (lol) I would recommend a Yamaha Scorpio as a good learner bike, particularly for a small statured person, they are light and i got mine lowered through the front forks by my friendly motorbike shop (for free). It was perfect for me anyways. Good luck

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