Definitely, absolutely, no question about it, join a choir. Doesn't have to be a church choir, or a religious group, in most populated areas, there will be a lot of choice.

And (I speak from experience), almost all choirs have a surfeit of female singers (sopranos and altos) but are direly short of lower-register voices (tenors and basses). So if you can sing in the bass clef you will be welcomed with open arms.

And don't be put off if you can't read music very well - a good ear will get you through a lot and sight-reading ability will come with practice.

Some choirs require an audition, which can be off-putting. My main choir doesn't - we run a system by which new voices can try us out without an audition for a few weeks. They are given a mentor, who is responsible also for listening to them to see if they can hack it. This seems to work very well and is more user-friendly than auditioning.

If they have a good conductor and voice coach, most choirs get steadily better and better. I have kept up with my folk-singing and have found lots of benefits there, too.