Good size for first motorcycle?

buy a well used 250, you'll get one quite cheaply with a little gravel rash on it. Just make sure it starts & runs well & doesn't blow smoke or mechanically noisy. Take a motorcycle learners course. different places different names for the course. Buying junk Chinese bike not worth it. Because of your size you'll do better looking at a standard or dual purpose rather than a boy racer style.

Your first choice is a poor one, used to own a '64 Honda 90 that stock went 60+ mph.

Your size versus the bike size is irrelievent at this time, you don't know how to ride and bike-wise the bigger for a beginner the not wise.

Look for a nice used Japanese bike, a $400 Chinese POS is pointless to own.

Get your learner's permit. Take the Motorcycle Safety Foundation course in your area (if you're in California, take the CHP course).

Buy a used Kawasaki Ninja 500, or Suzuki GS500 (whichever has service more convenient to you). Check Craigslist in your area.

All that a pit bike will teach you is the operation of the controls, it will not teach you how to ride. Your money would be better spent on a professional training course and a small displacement, secondhand bike. Get on the road and learn there.

Those bikes are so bad, you won't learn to ride before it breaks down.

You may become a decent mechanic though.

Buy a used 'name brand' bike.

With your hight I would so with a 250 cc dual sport that way your not cramped up and can ride street or dirt.

Oh forgot to add this to question....the bike says it adult size and I think it said tlit had 18 inch wheels. It says it goes 57+ mph. How fast around would it go with me on it do you think? Thanks for all answers and imput