Well since I have been young, middle-aged and now 70+ I can stipulate without reservation that there was no significant difference in tone, quantity or quality of flatulence in all three periods.

I think younger people, especially late teens and 20s go out of their way during prime mating periods to not offend and thus are vastly more adept at hiding and distracting others while cutting a little cheese.

Alas, it's a skillset that diminishes over time, but hey, we can't retain everything.