[2] Álvarez began boxing at the age of 13 and turned professional at 14 under the tutelage of her father Ruddy Peña.
[3] Álvarez made her professional debut at the age of seventeen, on 29 June 2000, winning a second-round technical knockout (TKO) over Natali Lara.
She won her second bout, before losing a six-round unanimous decision to Gisselle Salandy on 8 August 2000.
[4] Álvarez would go 12–0–1 in her next 13 fights, before losing a ten-round decision to WIBF flyweight champion Regina Halmich on 17 January 2004 in Germany.
[6] In her next fight, Álvarez lost a six-round unanimous decision to future WIBA flyweight champion Melinda Cooper.