I am happy to let kids and interested folks have a look as they're getting off. can't do it in the air.
ask the cabin crew nicely when you get on the aircraft that you'd love a peek when you land as you're considering a flying career.
most will gladly accommodate you.
an alternative is to go on one of those sim 'experience' days as you'll actually get a shot and the guys working the sim are normally pilots so you can ask them some questions.
I once 'flew' a BA 747 from the FO seat when I was '9' years old in the cruise. ( I presume the autopilot was on..........) the two lads thought it was hillarious. I almost wet myself, absolutely hated it......yet here I am doing the exact same thing.........