how to understand this sentence

Sorry, i got it. I looke up " opportunity cost" in the dictionary, and I got it. For the underlined part, I think it means " I wanted to do someting which my heart desired most" Am I right?

Yes, you're right.

You could boil it down to "I did what I wanted to do." or "I chose the option which most appealed to me"

Is it the "sort of went" the thing that confused you? It's not good English. It's casual, conversational English.

and sort of went where my heart desired

also means . . .

and kinda went where my heart desired

and somewhat went . . . .desired

and went where my heart desired, after thinking about it a little bit