What is a saying for "a bookish inexperience preaching the experienced"

One classic idiom/proverbial phrase is "teach [one's] grandmother to suck eggs." Here is the entry for that phrase in Longman Dictionary of English Idioms (1979):

teach one's grandmother to suck eggs coll[oquial] to try to teach, inform, or give advice to someone who is more knowledgeable or experienced than oneself: he is always telling the director how to run the business; that's like teaching his grandmother to suck eggs {V[erb phrase]: often in Neg[ative] commands or advice, as in don't try to teach your grandmother to suck eggs}

Cambridge International Dictionary of Idioms (1998) reports that the idiom is primarily British and Australian:

teach your grandmother to suck eggs British & Australian to give advice to someone about a subject that they already know more about than you | You're teaching your grandmother to suck eggs, Ted. I've been playing this game since before you were born!

And the entry in John Ayto, Oxford Dictionary of English Idioms, third edition (2009) includes a brief note on the history of the expression:

teach your grandmother to suck eggs presume to advise a more experienced person. | The proverb you can't teach your grandmother to suck eggs has been used since the early 18th century as a caution against any attempt by the ignorant or inexperienced to instruct someone wiser or more knowledgeable.

One fairly early published occurrence of the expression appears in Simon Wagstaff [Jonathan Swift], A Complete Collection of Genteel and Ingenious Conversation, According to the Most Polite Mode and Method Now Used at Court, and in the Best Companies of England (1738):

Miss. Lord! I have torn my petticoat with your odious romping : my rents are coming in ; I'm afraid I shall fall into the ragman's hands.

Neverout. I'll mend it, Miss.

Miss. You mend it! go, teach your grannam to suck eggs.

And from Henry Fielding, The History of Tom Jones, a Foundling (1749):

'I should not have mentioned it now,' cries Partridge, 'if it had appeared so to me ; for I'm sure I scorn any wickedness as much as another ; but perhaps you know better ; and yet I might have imagined that I should not have lived so long, without being able to distinguish between fas & nefas ; but it seems we are all to live and learn. I remember my old schoolmaster, who was a prodigious great scholar, used often to say, Polly matete cry town is my daskalon ; the English of which he told us was, that a child may sometimes teach his grandmother to suck eggs. I have lived to a fine purpose truly, if I am to be taught my grammar at this time of day. ...'

Thomas Fuller, Gnomologia: Adagies and Proverbs; Wise Sentences and Witty Sayings (1732) includes "Teach your Grannum to suck Eggs" (as well as the closely related "Teach your Grannum to spin") but doesn't offer any further discussion of it. Forty years before Fuller, John Hawkins, The English School-master Compleated (1692) has an entry for "Teach your Grandam to suck Eggs." in a list of "English Proverbs Alphabetically placed." So the expression had already achieved the status of a proverb in the late seventeenth century.

I’ve heard this called “book smarts,” which implies a lack of practical experience. A more humorous description is, “well-read virgin.” More negatively, “smart ass” or “smart aleck.” I haven’t heard it in general use, but there’s a classic turn of phrase from an ancient Hindu scripture that’s stuck with me as a good description of this, of a student who “came back, full of knowledge,” and did this.