Answer :
well if she has anxiety it could be that but it also might be a normal flinch or someone could be hitting her like her dad so she is scared of guys
In reality she’s probably being abused or was abused at one point and this is her trauma responding so if you think your comfortable and she’s comfortable talk to her and if it’s really bad, tell your mom or dad and see if they could do anything because if she’s just a kid, she can’t protect herself