I havent found a really definitive sizing chart. I have heard that you should get a slightly smaller size than they recommend. I am about 5'1 still growing. What is a good size 4 me?

create an account at https://www.wrenchscience.com and click 'fit system'

also, your local bike shop should have a variety of bikes to test ride.

be prepared for everyone's suggestions to be different. pick what feels right to you

i'm a hair under 5'2 and i ride a 49cm

There isn't a definitive chart cause everyones body is different. As a general rule you want the top tube about an inch below your inseam

The standover rule is pretty useless for short people like the OP and me (5'-3"). I do not have any standover clearance on most of my bikes with 700c wheels, yet they fit me properly when riding them. The main thing is to achieve the proper relative position of saddle, bars and pedals.