There are easily over a dozen online groups just on Facebook that are specifically for our age group. Most are women-only, although a few are co-ed. Some are very active while others see only a few messages a week. They are almost all private groups, and most do not allow outside links or sharing of posts. That makes them safe places to talk, ask advice, and vent. They are supportive and sympathetic.
Newcomers with questions are welcome. Many groups have directories so members can find each other. A few are discipline-specific. These groups are listed roughly by how active they are.
In addition, if you travel and camp with your horse, there are several groups of interest in the “Traveling with your Horse” section of the Resources.