To answer your first question, age itself would not necessarily prevent me from staying interested in and playing the game, but I would probably have to take in quite a few other factors, as well. The age itself is most likely not what would prevent me from wanting to continue playing, but I would presume that I would not have as much free time as I do now, along with other things such as: Perhaps a job, a career, other priorities, and other things that I haven't yet experienced. While Feral Heart will always have a special place in my heart, I cannot say with certainty that I would be able to see it in the way that it is currently. That's not to say that it's not a possibility, though-- and it would certainly be a neat thing to be able to come back and reminisce-- and if it felt right to continue playing the game, I wouldn't stop because it's often socially-understood that older folk cannot enjoy the games that they used to love due to its more childish nature.
For the second question, I could understand if they had a love and interest for the game, although as a few have mentioned before me, I would be a little cautious. If I were to put myself in their shoes, however, I don't think I would have much to say against them. It's sad that nowadays we immediately consider anyone who is an older citizen that plays a game geared toward a younger audience to be a sort of suspicious figure, although it's a sad reality in occasional cases. As long as they acted in a kind way and weren't doing anything to harm anyone, I wouldn't have anything against them playing and joining in with the fun, too.
