It does seem like some people's hair magically changes over time. I had this hope too, that if my mixed 4 hair grew long that it would weigh itself down and become pretty.... False!
The back of my head, 4b/c, when straightened, is at the middle of my back. But it shrinks up in to a puff at my neck with no definition at all when wet. No matter how long it gets, it's not changing!
Every head is different though.. but don't count on it.
I've heard of women, after pregnancy, being graced with either wonderful, tame hair, or being so nutrient deficient that it falls out. I've seen it, curlies/wavies getting pregnant and their hair becoming nearly bone straight! Ahh, that's another thread...
~My salvation lies in your love... Alexi Murdoch~