Hi, Though my grandfather is very old - over 80 years of age, his eyes are still quick and expressive, and his mind is still very intelligent. I'd write it this way. Though my grandfather is very old, over 80 years of age, his eyes are still quick and expressive, and his mind is still very intelligent.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.