does he appear in any fictional work?
The title character and protagonist of J. R. R. Tolkien's 1937 novel "The Hobbit", a supporting character in "The Lord of the Rings", and the fictional narrator of all Tolkien's Middle-earth writings.
Bilbo Baggins
Bilbo Baggins is the title character and protagonist of J. R. R. Tolkien's 1937 novel "The Hobbit", a supporting character in "The Lord of the Rings", and the fictional narrator of all Tolkien's Middle-earth writings. The Hobbit is selected by the wizard Gandalf to help Thorin and his party of Dwarves to reclaim their ancestral home and treasure, which has been taken over by the dragon Smaug. Bilbo sets out in "The Hobbit" timid and comfort-loving, and through his adventures grows to become a useful and resourceful member of the quest. 

how old was bilbo when he found the ring 60 years old.
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Bilbo Baggins [SEP] Introduction
Bilbo, defined by tobacco and a postal service, would be English, middle class, and living in the Victorian to Edwardian eras; this is not compatible with the much older world of Dwarves and Elves. Tolkien appears to have based Bilbo on the designer William Morris's travels in Iceland; Morris liked his home comforts but grew through his adventurous journeying. Bilbo's quest has been interpreted as a pilgrimage of grace, in which he grows in wisdom and virtue, and as a psychological journey towards wholeness. Bilbo has appeared in numerous radio and film adaptations of "The Hobbit" and "The Lord of the Rings", and in video games based on them.