Potty training 20 months!!

Holleigh

This is my first shes 20 months im pregnant with my second and would like to have my first potty trained before the arrival of my second. My question is..its been 4 days and shes only peed on the potty 3 times total. She will sit on the potty and not go and within mins of me taking her off she pees on the floor. Im giving praise and rewards. She isnt afraid of the potty and will notify me when she needs to poop so no poop accidents thus far, but when it comes to pee its like she doesnt get it. Everyday she doesnt pee at all between 11am and 4pm. So im sure shes holding it and she cries when she pees herself but for some reason its like she doesnt know she should pee on the potty. Do u think she is possibly too young to grasp the concept at this point? Should i keep trying or take a break and try in a few months. I just feel like im at a total loss at this point.