it takes nine months for a human baby to grow, 22-months for a much larger baby elephant to grow...but how long does it take to grow a planet? it turns out, it takes much less time than we thought.

How would the previous sentence be correctly capitalized?
It takes nine months for a human baby to grow, 22-months for a much larger baby elephant to grow...but how long does it take to grow a planet? It turns out, it takes much less time than we thought.