I started with Airbus X, because it looked nice and the systems were not so detailed (But after a while it is a little bit boring. I was not happy with this product after some time). After that I bought the PMDG MD-11, then the 747 and now the 777-200LR/300ER.
I think you can start with a little bit training with the T7 (Documents, Videos,....) . Enjoy it. The 777 makes a lot fun, is very detailed and looks beautiful.
P.S: When I started with this professional Airplanes, my first flight was a little bit "horrible". But after some training this kind of flying was wunderful and I am happy that I started with it.