I am creating a program that helps people learn a growth mindset and “grow” into what they want to become. Is crescere the correct word meaning to to grow or cultivate?
I think crescere is an excellent word for growing, be it concrete or spiritual. Check its dictionary entry in Lewis and Short. It can be used in sentences like "I grow to be a better person" and "the pumpkin grows".
If you want "I grow pumpkins", the word crescere is not suitable. It is intransitive and the subject is the one to grow. If you want something transitive, like "cultivate", I recommend colere. Check its entry in L&S to see a range of meanings. In fact, the English "cultivate" comes from this very verb.
So, the person or thing growing crescit and the person or thing that helps something grow colit. The choice of words and especially forms depends on how you want to use these words. If you want to ask about sentences or short phrases using these words, I recommend asking a new question focusing on syntax.