One thing I believe is that if you don't enjoy what you're doing, it's unlikely you'll be able to sustain it. So I think the first thing here, to my way of thinking, is to find something you genuinely enjoy. I know yoga has been suggested. Tai Chi is another eastern discipline that might be of interest.

Here where I live there are always adult community education classes that are offered at either no cost or minimal cost. If these sorts of things are offered where you live, it would be a way to try out different things & try to find something you enjoy enough that you're likely to stick with it. I've done both yoga & Tai Chi in the past. Currently my own exercise routine consists solely of walking our dog. He gets 2 long walks every day regardless of the weather. Lately it's been a real challenge!