I would keep it long enough for a ponytail. Nothing is easier then throwing your hair up! If you go to short I feel like you have to style it everyday! I am getting about 4-5 of my hair but I need my ponytail/bun!
I always heard not to cut your hair or do any changes while pregnant because you might be Using your pregnant brain to make a decision you will regret 😂 However it looks like you will have your hands full soon so I say do what’s easier. My hair would be more work if it was short and a ponytail is very convenient for me. But most people have easier hair than me!