Ladies Bikes - What are you riding?

Shoosh, please don't take offence but it might be worth looking at Isla Bikes. They make kids bikes but their largest kids track bike will be about right for you (hard to say exactly as it depends on more than just your height).

Check this link and click on the Reis 700.
http://www.islabikes.co.uk/bike_pages/reis.html

The benefit of 700c wheels means you'll have a far bigger choice of tyres let alone rims if you ever need to replace them/upgrade them.
You'll need to also buy brake/s depending on if you want to run it single speed or fixed but it is still a bargain in my opinion and although they are made in the far east it is a small british company run by a very nice lady.

i agree with Tim's advice. Cisco's got one and it takes loads of abuse, even big boys riding his bike. The little bike is really though! I was eyeing an isla track bike at the track and they are sweet.