Welcome to the forum! Yea choosing the scale type is going to be up to you and related to the mood you're trying to convey in your song. As @edburdo mentioned, simplistic reasoning would say that major keys sound happy and minor keys sound sad, but of course that all depends on tempo, lyrics, progression, etc.
I'm sure there are probably some articles and essays out there which go into more depth and perhaps provide some logic on which keys / types of scales sound best for certain types of songs. I've heard people say that Eb conveys a different feeling than Bb, etc. I believe it does, but I haven't been able to mentally materialize what that feeling is exactly yet. At least not in a way where I can describe it verbally.
I'd say ultimately it's going to be whatever sounds best to your ear. The more songs you write the easier it will become to chose which keys work best for you. Hope that helps!