Hi Ivy. Till now have u tried having a feel of sitting on a bike
and feeling the weight etc yourself?
Coz when when u sit on it, the height of the bike will lower due to
your weight compression. And when the bike is on centre of gravity,
it's stability is not as bad as you might think.
About your height, there's no limit to it, as long as you're able
to pass.
I suggest you should enroll and see how it goes, proper instructors
will guide you through.
