An audience can be created by clicking on “+add segment” at the top of nearly every Google Analytics interface. You can choose from a vast variety of different characteristics such as age, interest, device used, or traffic source. With that, you can dig deeper into analyzing specific user groups you might be interested in.
You could, for example, investigate the metrics of your elderly targeted group derived from your Facebook marketing campaign and see if the bounce rate is similar, higher, or lower than other target groups. A significantly higher bounce rate would signal to work on your first screen of your Clickflow to be more appealing to older age users or adapt your Facebook marketing campaign.