I would say about 20-30, so that I could take care of myself, because if I was younger, I wouldn't know how to take care of myself, because my parents would age, and I wouldn't, so everyone I knew and loved would die before my eyes. If I was any younger, I'd take it really bad. If I was older, than I could possibly handle it better. Also, if I had a choice, I wouldn't want to stay the same age forever, because thought it might seem great, living forever, what if you get sick with a disease with no cure? Then you would be sick and suffering forever. Also, as I said, people you all know and love would die before your very eyes, and it would be really hard to socialize and make friends because while they grow up, you won't.