What is the average age you would say that go on these tours?

any early-mid 20 year olds?

There are sometimes a few early-mid 20 yo on those tours, but as a general rule they would be travelling with parents/family members. The average age is around 45-55, but it depends on time of year and tour type.

If you are looking for tours which are "younger" then try Contiki, Top Deck, Busabout (hop on hop off tours where you can build your own itinerary) or boutique companies like Quo Vadis Holidays (30s-40s) or Intrepid (smaller groups, vast age range from 20 - 60).

I think these are really for the over 45's unless you are traveling with parents.
It is not something to consider in your early 20's.

Yea, I'm traveling with my mom and I just have a strong feeling I'll be the youngest. Was just curious..thanks

The only tour I was on I was almost 30 and I was the youngest - next nearest was there with her mother. Most were older than my parents (but that was the only way to see Russia then).

I think I'd be the youngest on a Trafalgar tour and I left 20s in the rear view a while ago.

I'd probably be young enough to be the next youngest someone's kid on Cosmos . . .