I think black looks really good on you, so I'm not sure why anyone would say you wear "too much" black. It's a very good neutral for you, and I don't see why it can't be one of the core colours in your wardrobe. It looks fab on you!
When people say "too much black" - it's because they've read something somewhere saying that one shouldn't wear too much black clothing, but I think this only applies if the colour isn't as nice on a person as it once was. I used to wear a lot of black (still do actually), but in my own case, I notice it's not quite as flattering on me as I get older. I try to remember Angie's tips re: adding a splash of white/cream near my face or what have you.
In your case though, black actually looks great on you, so any advice such as, "Don't wear too much black" doesn't apply. These days, navy/ink blue looks nice on me, and wouldn't it be silly if people said I wore too much blue? Angie looks amazing in those cream colours, blush colours and the like - whites are fab on her. No one would say "too much cream or white" now would they?
Never mind your MIL - it's just old "advice" that she's heard or read somewhere. Like not wearing white after Labour Day, or before May long weekend. Or trying to match your shoes to your handbag.
Meanwhile, it sounds like she is offering this up because she wants to have some nice female "bonding" time - and to talk about things like style, fashion etc. I get the feeling she really enjoys style and fashion and is enjoying participating a bit in your style journey.
I don't think there's too much black - how can something that looks good on you be "too much" ? She's just trying to be helpful and seems to like talking style with you. This is a good thing - I wish I had more people in my life who were interested in style matters My DH is a master at saying, "You look fine..." (aggghhhh....).
No need to start steering yourself away from a neutral that works well on you.
