Many of us got "curlier" after we learned to care for our hair. When I first started here, my hair was dry and damaged. The curls popped to life once they got properly hydrated and I learned the right products and techniques. It's not that the curl pattern really changed, the springy curls were always there but they were suffocated and parched. As your hair gets healthier, you're likely to see stronger curls.
I'm another one whose curls changed by learning to take care of them. I went from winter wavy/summer 3a to hair like my signature picture every day. I didn't use products (or technique) before I started lurking on nc.com a little over five years ago.
3a (Corkicelli), highlighted, fine, low porosity
modified CG, since April '07
CG since 3/11/08
HGs: Anything Sevi; Curly Kinks Satin Roots, Curlycue ReNew and Coil Jam; homemade FSG and okra gel; soap bars; UFD Curly Magic; Botanical Spirits Jellies, CJ Repair Me, Marie Dean Leave Ins and Curl Creams
My hair type has changed many times throughout life. I've been 2A 2B 3A 3B and nearly 4A at one point.
Most changes were probably hormonal, some changes were due to how I was treating my hair, and my curl pattern can also change depending on how long or short my hair is.