Him and Elizabeth were old - well beyond their once young and spritely selves. But then when the angel of god appears to him, he says "your prayer has been heard". So weird! Why in the world would zechariah be praying for a kid?? Being old, possibly knowing his physical and emotional limitations to raising a child, having a kid is cray-cray. Although being barren in those days was tough, he'd probably accepted it and learned to manage without diapers and teenage rebellion. Life as he knew it would continue with just the two.
And yet it seems like his desire for a child was something he secretly and continually prayed for.
I could learn something here.