Momma's of Adults

I'm a teen daughter with 2 adult brothers. Our mom got into a fit with my sister in law because she was saying some wild things about my other brother (the one she isn't married to).

Is it normal for mom's to still be all protective to their adult sons even if my brother's 25? i dont even think my bro was bothered but oh boy she went momma bear. Someone please explain haha, I don't think she'll outgrow her momma bear phase. Love her though.

Do you think she's being extra or is it natural mom instinct?