I have been getting an increasing number of videos suggested on YouTube from people who are posting about starting a channel after their 40s and 50s. Their idea is that the algorithms of YouTube will recommend things that you like and most people who are in their 40s and 50s are not going to be watching the same videos that younger Watchers enjoy. Therefore the reasoning is that older viewers will prefer older content creators. So now that I have reached the age of 50 I am seriously considering building my YouTube channel.
Ultimately you don't really know if it's going to work unless you try.