I'd say no. I think it varies from person to person but I don't think curiosity is lost with age, maybe the act of seeking answers to our questions dulls but the actual curiosity of things around us remains.

Not me. I am now closer to 40 than 30 and am considering night school for mechanical engineering because I want to understand how EVERYTHING works.

Hahah that's awesome, definitely do it especially if you're passionate about engineering. It's never too late to learn, I think people sometimes limit their opportunities on this invisible boundary of age.

I think it isn't we lose curiosity it is we just already learned to figure things out on our own so we ask about stuff less out loud because we just ask ourselves for the answer.

But as for always learning new things I do that every day. Just yesterday I looked up The Field of the Cloth of Gold which had King Henry the VIII and King Francis I.
I think everyone should learn new things every day.

I couldn't agree more. It was just a thought i had, because after speaking with people they've never really given into curiosity about much.