i am over 40, black hair, fair complexion. i want to go to long layered cut. would "frosting" work

I'm not really sure what you mean by frosting. If you mean hair color, I would be careful. Definitely find a colorist who knows how to work with curly hair. Too often, frosting or highlights can come out to brassy on curls. If it's a type of layering, I'm not sure I've heard the term before.

I am 44 with a fair complexion & very dark brown 2C (a little 3A) hair.  The length is to the center  of my back with long layers.  It took 41 years of trial & error to find the right stylist.  She adds a couple different color highlights (they don't say "frosted" much anymore) : one just a couple shades lighter than my natural color, & a caramel color.  With that, & finally learning how to get my hair healthy - soft, shiny, & with defined (minimum frizz) curls, I love my hair for the first time in my life... & I get compliments every day :)  I'd highly recommend seeking out a good curly stylist & give it a try!