I'm curious about resistance and side effects of wrinkle Botox!

Hello. I have frequently visited dermatologists, but for some reason, I have never received any type of Botox, such as wrinkle Botox. However, I have a horizontal wrinkle between my eyebrows, and it seems to be getting deeper, so I am wondering if it would be better to get wrinkle Botox before it gets any deeper.
First of all, I'm wondering if I can assume that I won't develop resistance if I get the German-made version? I'm worried that if I start getting wrinkle Botox when I'm young, it might not be effective when I really need it later on.
Next, I heard that if you get Botox for frown lines incorrectly, your eyebrow shape can become distorted. Is it true that such side effects are quite rare...?

I know a lot of people get Botox, but I'm worried since it's my first time.