No. This sentence makes sense, and it translates your idea, however, this would not be said. A better way to phrase this would be to simply say, "Even adults should get new knowledge.". The part about children is implied with this sentence. Or you could even say, "Adults should get new knowledge as well as children.". And just a suggestion, even though it is grammatically correct, "get new knowledge" is not commonly said by native speakers. A more "fluent" way to say this would be to simply say learn. :)

It's not a common phrase, so there really isn't a correct way to say it... There are, however, several ways to say it. Both children and adults should take the opportunity to educate themselves further. Kids aren't the only ones that could benefit from more education. (proverb.) Even old dogs can learn new tricks. Etc. The way you've phrased it isn't wrong, but it isn't right either.

i think u should use '' but also'' instead of ''even'' . ''not only'' always comes with ''but'' or ''but also''