as with most anything (difficult) is relative.
are you a fairly good piecer?
are you a precise cutter?
are you patient?
some people think of bargellos as a fairly easy (beginner friendly) project, other's find them to be quite difficult.
i think of them as kind of an intermediate/beginner...if you pay attention to detail- take your time- and cut/sew fairly precisely they would be easy for you- if those technical steps are difficult for you- it will be a little more difficult (but certainly not impossible)
look over the tutorials, videos, and all the patterns you can find- read the hints and tips- and before committing to a queen size bargello- maybe make a table runner- or a tree skirt bargello---they you will have the process figured out- and know if it's something you want to make a big quilt out of.
personally- i love making bargello quilts!
they are aways so unique--at least mine are.