Typically, the reaction would be one of deep befuddlement (particularly from other children: “removed from what??”) Meanwhile, anyone vaguely familiar with the workings of kinship would hazard tentatively, “But if they’re once removed…why are they the same age as you?
Here is a general summary of United States law regarding marriage from Law QA by Total Attorneys, but it is important to remember that the laws vary from one state to another.
Scripture does not prohibit marriage between first-cousins. First, it would be a serious error to say more than what scripture has said or to add to scripture.
Second, we are assuming that when you married in the United States, you did not violate any of the laws in the state in which you were married.
English is sometimes irritatingly vague when it comes to kinship terminology, even within fairly close family relationships.
I can’t tell (without more context) if your brother-in-law is your sister’s husband or your husband’s brother.