Emilia comes from the Latin Aemilia, the feminine of the Roman family name Aemilius — possibly from aemulus, meaning "rival" or "eager." The same root gives Amelia (which entered English via the Germanic line) and Emily (the simpler English form).
Emilia rose dramatically in the U.S. Today Emilia sits in the U.S. top 100.
Emilia does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Emilia reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.