It doesn't really matter if you scare someone you don't know. They don't know you either. Ultimately it's reasonable to be uncomfortable around strangers.
If you still scare people even after interacting with them, don't take it personally. Lots of people have biases and past traumatic experiences that might paint you any which way.
Just focus on being kind and liked by the communities you're in, and don't take a defeatist mentality over someone being scared of you at first.