One of the interesting things I have discovered on the internet is that there are a surprising number of people who express an interest in learning to play the cello somewhat later in life. As seems common today, there is a strong DIY trend that seems to accompany this. While many people have experience teaching themselves to play the guitar or keyboard, I tend to discourage this with the cello, as it is simply too easy to do it wrong; not so much in defying “tradition,” but in the very real possibility of injury. Playing the cello is simple, in that there are some very basic principles that are at work to make the cello sing. But those “simple” tasks involve a lot of repetitive motions that even done well can produce nagging health problems. For this reason, and because it is possible to make far faster progress with help, I encourage people to find a good teacher.
A local symphony, the music department of a college, etc. are good places to start.
You can go to these resources for advice in finding someone in your community. You do not want to study with someone who teaches general strings unless they are a professional cellist, as while there are commonalities with other members of the bowed string family, there are also radical differences, principally as the cello is approached in the opposite manner of the violin and viola. While I have learned an enormous amount from violinists and pianist over the years, I did so as someone who already had a good foundation at the cello. So, I strongly urge that the person you study with be a competent cellist. The cello has particular requirements that you must get right, and you can only get that from a cellist.
For many beginners (even adults) Suzuki training is a good way to start, and it offers the social aspect of working with a group at least part of the time.