Hi, first I want to ask about how to find the key of a song by listening, is it always the first chord in the beginning of a song? If not, then how to determine the key of a song that begin with the chord other than the key of the song?

Second, after I find the key of the song, how to predict the next chord or the progression up until reff section which is usually have another set of chords.

My goals is to be able to find the chord instantly whenever I have a song in my mind.

Thank you :)