At least, also remember:Awesomeness In a nutshell.
That's the size of, what, a Light Mech at least?
1) R2-D2 is small size so for him it might not be light to him
2) That thing is at least 30ft tall before extending its digitigrade legs which would put it around the same size as a normal AT-ST.
3) That mech has way more support than most Star Wars walkers, I don't remember how much an AT-ST weighed but canonically it could carry three people and 500 tons of cargo and typically a light mech weighs under 30 tons