Well you didn't chose the easiest of names, but Garcilaso de la Vega el Inca is a much more beautiful name than Caius Flaminius imho. It has more class and style

If you like it, keep it. Don't mind those slackers like me who want you to change it back to Caius just because they are too lazy to get familiar with the new name.

In time, people will get used to it. After a while I myself will probably start calling you "Garci" or "GVI" or something, just like Caius Flaminius got abbreviated to Caius after a while.