I'm almost 50 and did my first solo cruise this past June. I loved it and am doing another in a few weeks. I never felt unsafe. I don't get bored easily in just a week and made friends on the cruise who I could join for trivia or a drink. I'm ok with approaching people to see if i can join their team. If you feel comfortable with that, i think you can definitely find enough to do. Some invited me to join them for dinner but I chose to eat by myself for the wind down after touring all day. Also didn't want to be on someone else's schedule.
I do Instagram stories so the feedback helps me feel like I'm sharing the views with others. I don't do it for this but realized that my friends commenting on gorgeous views probably helps me feel like I'm still sharing the experience.
I would to try it. If you hate it, just don't do it again. If you like time on your own and are considering it, give it a chance.