Which bachelor's degree would be most helpful for practicing as a PMHNP?

Hi all! I have been reading this forum for a year now and have really learned a lot. Thanks!!!!

In my younger days I just wasn't cut out for school. I was far too much of a dreamer. Now I'm 37 and about to finish my third semester of an ADN program. Although I have matured (somewhat) in my outlook I still intend to change the world. I see myself eventually working in the public sector as a PMHNP. I would like to achieve this within six years or so.

MY QUESTION: I don't have a bachelor's degree. Should I get a BSN or should I get a degree in something else like Spanish (I'm bilingual but not fluent enough to do therapy in spanish) or exercise science (I'm very interested in the relationship between physical activity, especially distance running, and mental health) or what about psychology? I know some schools want a BSN for admission but others (for example UCSF) have told me they don't have a preference and to just pick something that I think will help me be a better nurse.

What do you think?

Thanks in advance for your consideration!!!