We must bear in mind, tho', JUDE, that for a hobbit 50 years-old is just reaching maturity. I gather he was barely an adult!
I hadn't thought of it that way, JOANK, but you are so right. Tolkien's writing is lyrical, and I find his songs a delight. Watch for the change in tempo between, say, the song of a hobbit or elf, and those of the goblins.
As to why Gandalf chose Bilbo, so far I can only see that for some reason he needed a hobbit, and the Took bloodline
was the only one that might be persuaded to go. He started right in with stirring up the little hobbit, didn't he? A simple 'good morning' and he's demanding to know what he means. 'Good morning' is plain enough for anyone, but Gandalf lists at least three different, tho' unlikely, possibilities. I heartily approved Bilbo's calm response, "All of them at once", and adding, 'and a very fine morning for a pipe of tobacco out of doors, into the bargain".
Gandalf then announces that he is there to find someone to share an adventure, and finding it very
difficult. Whereupon the Hobbit explains for us just how Hobbits regard 'adventure'. "Nasty disturbing uncomfortable things! Make you late for dinner!" Bilbo's naive idea of an adventure is anything that makes you late for dinner!