I think you should try and do the things that make you happy. I have a few hobbies/interests that others might see as immature (one sort of current hobby is painting tiny horses to look like the 80s My Little Pony toys. I’m planning to put them on necklaces later and sell them, but mostly it is an excuse to indulge in childhood nostalgia!) My hobbies don’t harm the people around me, but I do understand the feeling of being judged for enjoying them. There are certain (totally innocuous) sites I go on every day that I’d feel wary of looking at on a library computer, because other people there can’t seem to mind their own business.
Lastly, I don’t know how you feel about not having many friends but I would be irritated at your siblings’ pity as well. Years ago, I heard snippets through my mum that my brother had his own sort of narratives as to why I had virtually no friends (aside from my mental health issues, it’s turned out to be more complex than the explanations he came up with, anyway). Truth is, at that time I didn’t care at all. A lot of people just have this idea of what your life should look like, without considering whether it’s really what you would want for yourself. If you do want a larger social group that’s fair enough, just don’t feel pressured into trying to fix it because of your family’s comments.