Wow, I have to admit, but it's surprising you can do that well at the age of 11. It's incredibly impressive, not gonna lie.
Anyway, I see you are trying to pressure the other person more. As mentioned by PHP, your best options in neutral move-wise are f-air, b-air, full-hop n-air, jab, d-tilt, and grabbing (standing grab is more preferable). However, I would also throw out autoreticle at some time if my opponent won't approach me. Ledge-cancelled up-b might be an option as well. You can try short-hop f-air camping if your opponent is trying to approach you. You can space yourself carefully and jab when your opponent is trying to attack you. Jab is so disjointed that it is useful for punishing extended hurtboxes.
You can also mix up your movement options to add more depth into your gameplay. I see from the video that you like to use run-up shield and run-roll back. You can also try to use some EDD to confuse your opponent and bait out some attacks more. Perfect pivot is also a lot more helpful than it seems, as well. For instance, it gives you the ability to run back and quickly turn you towards your opponent quickly. You can also try using more empty hops to punish shields more easily.
Also, if your opponent likes to shield when you approach, try some cross-ups. You can punish your opponent according to their reaction to your cross-up. For instance, if they drop shield the moment you jump, you can d-air. If they continue to hold shield, you can land and dash-grab him. If they drop the shield later when you are behind him but still in the air, punish him with a b-air.
I could go on, but applying all these things together will make you more unpredictable. Try these things out, and you'll see that Palu's neutral is rather deeper than most people would give credit for.
