I faced this factor last year when I decided to buy a first telescope for my 8-year old granddaughter.
I believe that there's one additional factor that should always be considered: the capabilities of the intended recipient. I faced this factor last year when I decided to buy a first telescope for my 8-year old granddaughter. I ended up buying her a 76mm tabletop Dobsonian scope because this was one that she could carry in and out of the house herself and, when set on the back yard table, had the eyepiece at an appropriate height for her.