To the OP, it sounds like in your case your hair will probably get a little curlier if you cut it.... unless you think your curl pattern actually changed in the last few years or months...sometimes this happens.

I'm 2b and there's a bell curve of curliness that happens depending on length of my hair. Before, when my hair was short it was almost straight, shoulder length to midback is probably the waviest/curliest. Any any longer and the wave becomes lazy. But my hair never has the curl potential that yours does so I think yours would probably be curlier if cut shorter.

If thin is really the issue that is bothering you remember that shorter hair looks fuller. If on you it will get curlier as well that may be an advantage as it will add even more body.

Post pics of the changes if you decide to make any!