Pretty predictable. The younger generation of Russians mostly want nothing to do with this war. Let the older Russians who support Putin go and fight for him.
That's a good point. The 8-10 million Ukrainians who have fled the country are those who are young, or have the $$ to do so.
Just from looking at many MSM photos of both sides - I would guess the average age of Ukraine vs. Russian soldiers is at least 20 years older. Certainly all the recent photos of Ukraine fighters look like old greybeards or pot-bellied middle-aged guys.