I’m a relatively new player who is wondering weather I should be playing with J4 to start with and move up to J5 or if I should use J5 now
Probably just stick with J4 for now. Higher judges are useful for fine-tuning your accuracy, but its unnecessary when you’re still learning the game.
I recommend you start playing J4 so that your fingers become independent. In a future, you will need to focus on accuracy, that’s when you start using J5.
I wish you had some scores to accompany the post, but considering you say you’re a new player, I’m going to agree with the other posts so far. Stick with default judge for now. There was a thread like this a while ago where some of us talked about when one might switch to J5, and also about the benefits of learning the error bar (which I recommend if you can). You can view some of our posts here: J4 vs J5 thread