Having never liked Metal when I was younger, I can't really comment on the whole "you'll grow out of it" malarkey from firsthand experience. And it is malarkey, as that 'saying' carries with it an implicit condemnation of the medium itself - essentially, that you only ever liked it because you were a kid and kids are stupid, thus making the music stupid.
Which is a load of crap - there are terrible Metal bands that kids do in fact like because kids are stupid and like crap, but the same could be said for just about any other genre you might care to name; Metal isn't an inherently childish genre that only 'musically retarded' individuals keep liking into their adulthood, and anyone who tells you otherwise is either speaking from a position of musical ignorant and not experience (best case scenario) or just a jackass (most likely scenario).
Keep on rocking out unashamed.
Which is a load of crap - there are terrible Metal bands that kids do in fact like because kids are stupid and like crap, but the same could be said for just about any other genre you might care to name; Metal isn't an inherently childish genre that only 'musically retarded' individuals keep liking into their adulthood, and anyone who tells you otherwise is either speaking from a position of musical ignorant and not experience (best case scenario) or just a jackass (most likely scenario).
Keep on rocking out unashamed.