Advice needed: Should I choose Spanish or Mandarin, or both?

Hi! My husband and I are about to have our first child. We’d like to raise our children to be bilingual. But we’re not sure which language to prioritize: Mandarin or Spanish (or both???). We are both from and live in the states.

English is our first language, but I’m close to fluent in Mandarin (intermediate level) since I used to live in China. I can converse mostly fine, I can still read and write. It’s a little rusty since moving back to the states 10 years ago, but I’m sure any lost skills could come back quickly with a little tutoring. Even though I’m more comfortable with Mandarin, I’m sort of doubting it because we unfortunately live somewhere that is not diverse at all - almost no mandarin speakers. So I’m worried they wouldn’t really get enough exposure, and it would be like swimming against a current.

On the other hand, I can speak Spanish pretty well. My husband is half Mexican but can’t speak Spanish, but his father is fluent (lives far but he’d probably visit once a year). He wishes he learnt Spanish as a kid, and feels like his culture/language was lost with him and wants to bring it back with his children. Spanish is also more useful in the US, and there are Spanish-speaking immigrant communities here, so I think there is more of an opportunity for our children to speak and learn Spanish outside the home. I’m just not as confident in the language as Mandarin.

I’d love advice from this community - especially if you are trying to raise your kids with a non-native language that you’re not or just semi-fluent in.

Our biggest questions are - does it make sense to choose Mandarin or Spanish? Should we start with one (in addition to English) using OPOL and maybe try introducing another later? Do you think it’s reasonable to even try to raise our kid bilingual with not 100% fluency? Did you take additional lessons or anything to improve your own language abilities before having a kid?

Any ideas or advice is welcome!