just curious... can hypothyroidism start developing in your early teens? I've had some of symptoms for a long time and wondering if it's why I felt so tired when I was a teen... another symptom I read is feeling the need to yawn to get in breath, which I've had on and off and always wondered what caused it.

I was 13 or 14 when I was diagnosed, so it can definitely start in your teens. I would imagine even earlier, but I'm no expert.

I've had it since I was born. It can start anytime. Definitely get it checked out with a blood test.

My friend had thyroid cancer at 19 so anything is possible.

I was diagnosed at 19...who knows when it came on, though.

I was diagnosed at age 9, along with my mother and 2 sisters.