I used NUK 18/36mo pacifiers for around a year.
Are they smaller than adult pacifiers? Yes, it’s not even close. That doesn’t mean they’re bad though… I still use mine sometimes, even though I have an adult pacifier too.
Honestly, if you want to try them, I’d say just do it, they’re pretty cheap, and worse case scenario, you have some cute pacifiers you can use to mod.