Selena is the Spanish and Latin American form of Selene — the Greek Selēnē (Σελήνη), meaning "the moon" and also the name of the Greek goddess of the moon (predecessor of Artemis/Diana).
Selena rose dramatically in the U.S. Today Selena sits in the U.S.
Selena 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 Selena reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.