But if the whippersnapper is actually honestly doing their job and learning I don't mind the questions one bit.
In my unusually long (for my age) working life, in my professional life, and in my recreational life I have met many people who are engineers, and many who are experts in other fields. Some of the names you will know I expect, as I've been blessed in that time with meeting some truly exceptional people (no doubt very few of whom could ever be expected to remember meeting me, but a few have become long-term friends).
Only once did I meet Sir Ancient GrumpenCunt, and for the first few years of our working together he truly was a grumpy old bastard who was deeply offended (later becoming a great friend and ally in the office politics). Part of the issue no doubt was I was brought in to help with a job he was getting too old to do, but he didn't want to admit it.
But the vast majority have been quite happy to pass on their knowledge, especially in situations such as you mentioned. They value people who are wanting to learn to do things the proper way rather than the modern 'get it barely functional before going elsewhere, don't care if it breaks tomorrow because it appeared OK today'.
I also count the likes of plumbers (not the sort who are lost if you ask them how to drill a hole in a 32mm PVC pipe), builders, proper electricians and my favourite, old-school mechanics (the sort who can cast their own pistons as good as any OEM, starting by making their own furnace, pots and molds if they don't already have one; who can find there's no available gear so cut and case-harden their own etc) among that lot - people who despair the loss of skills today and who are gladdened to see some keen to learn the skills, and are eager to pass on their knowledge before it is lost forever. True craftsmen (and women), not from-the-book/by-the-book only types (or "If youtube doesn't know how to do it, neither do I"
Er, yeah anyway.. Would you like cream or syrup with those wafffles? Have a beer for being one of the decent ones keen on helping others learn :)
 I was 5 at most when I did my first full-day of work, but I can remember being sent over to feed a neighbour's lambs at around 3. Can remember how far and how many worlds away it seemed..