Mothers: are you more protective of your younger son or older? or is it equal?

my boyfriend is the youngest of 2 boys and the youngest of 3 overall. his mother is very protective of him and kind of overbearing. to the point that she even tries to dictate the kind of girl he will marry. she really liked me before. she loved that I was smart and independent. but after he and I broke up (and I dated someone else) she naturally turned cold towards me. but even after we got back together, she is still kind of distant towards me. its like now, she wants her son to dominate me and not be with me unless i can be submissive to him and fit more of what she thinks a suitable wife should be like for him. I was wondering if shes just like this because he is the youngest or if she is like this with both of her sons. so that is why i am asking all the mothers here that question.thanks