It's up to you, but there's a few names which could also shorten to Bella, if you're not sure about Isabella. Gabriella Arabella Bellatrix Annabel / Annabelle
You can definitely just use Bella if that’s what you prefer! Personally, I love the name Isabella and then Belle for short but my brother in law beat me to it and named his daughter Isabelle so we can’t use Isabella now!
I think Isabella more commonly gets Izzy than Bella. You might need to correct to Bella
Yeah if you have your heart set on the name Bella stick to Bella. I have multiple friends called isabella who choose to go by izzy instead x
I think if you just refer to her as Bella from the beginning and rarely use Isabella then I doubt people will start calling her Izzy.
I had a coworker that named her daughter Bella. I think it's fine to use just Bella.