Trained, yes. But by far the least trained.
Altair was born into the order. Ezio started at age 17 and was active until he was, what, 55? And Connor came as a 14 year old and was able to kill a military general only three years later.
Edward was trained. But he got far less training than the rest.
His feats speak for himself. The others may have been officially trained, but it doesn't make them more impressive.