There is no problem with that. Only problem is being hardcore fanatic about things and making them into something, they are not.
Fanaticism makes an unbearable assholes out of people, but simply enjoying something you grew up on, like me, isn't problem at all.
It's just a series, form of entertainment. I am watching all kinds of stuff and reading books and comic books.
I have a broader view, as I like to self-educate myself in history, geography and demography, so I participate in lot of discussions
and besides that, I do enjoy music, art and movies, so it's not like only about Dragon Ball.
For example in work, someone notices that I like Batman a lot, so the discussion is usualy: ''Hey do you like Batman?'' ''Yeah, I've read a ton of comics and like it.'' ''Cool, I've saw like the last 3 movies and they were great'' ''Yeah, I like them too''
And that's it. Because I am not obssesed, so if the other person is not a huge fan, I don't pursue any further discussion, because it will end in being rendered to something simmilar to Yehova's witness.
So if you are normal person, being surrounded by normal adult people, it's okay to like whatever you like. You are never too old for anything (maybe for playing a child's character in TV series).
Just don't be a weird dick about it