I think the turquoise jacket is a beautiful colour and it *is* a colour that does seem to be almost universally flattering. Definitely not 'too young' or whatever. In fact, some of the neutral colours can wash a person out, and some of the vivid jewel tones or bright red are almost too much.
Not sure if it helps, but my Grandma turns 98 this fall, and turquoise is her very best colour. Way better than red, black, grey, taupe/beige or what have you. Makes her eyes pop, her skin glow. She has bright white hair, very fair skin and vividly blue eyes. Turquoise looks *amazing* on her. All the 'classics' (red, gray, black etc.), not so much, and you can forget about "subdued" (beige, taupe, off-white, some pastels) - they don't work either.
I hope you keep the jacket - I bet it looks fantastic on you! I would buy the turquoise myself (40's) and would definitely buy it if I were in my 60's too. Beautiful colour, and one that will go the distance - it's not too trendy, it's not too harsh, and it's certainly not too washed-out looking either.
Keep!