VS officially hires models only 18 and older since the Isabeli controversy but many recent models have been 16 or 17 years old. They mostly do Pink though.Getting a contract doesn't mean you're an Angel, there are different types of contracts, the "Pink Girl" for instance isn't an Angel, Lindsay and Emanuela were hired as spokespersons for BBV and weren't Angels. I don't think there's any age limit to be an Angel but if we follow VS's policy to hire only girls who are at least 18 and assuming they would only become Angels if they sell well, then you'd have to be 19 at least to be an Angel, with one year to prove your worth.
The Angels concept basically started with a campaign shot in 1997, which featured Helena Christensen, Stephanie Seymour, Daniela Pestova, Karen Mulder and Tyra Banks. For some reason it became widely popular and VS started thinking about using the term "Angels" for its biggest models, as Helena, Karen, Tyra, Daniela & Stephanie were already being called "the Angels" by the media.
During 1997-1998 Stephanie Seymour, Daniela Pestova, Karen Mulder and Tyra Banks were basically in every Angel related work, while other big VS models rotated around them. Helena Christensen did the 1997 Christmas catalog and the 1998 English Lace campaign, Laetitia Casta did the 1997 Christmas commercial and the 1998 Dream Angels campaign, Yasmeen Ghauri appeared in the 1998 catalog wearing Angels underwear, Chandra North did the 1998 runway show and Inés Rivero did the Angels 2000 (held in 1998) campaign and the 1998 Dream Angels campaign, which left us with Stephanie Seymour, Daniela Pestova, Karen Mulder, Tyra Banks, Laetitia Casta and Inés Rivero as the Angels in late 1998.
Somewhen between then and the 1999 show, Heidi joined the line-up and Inés was removed (although she continued to walk at the show until 2001). In Cannes the line-up was still the same but after that Karen Mulder, Laetitia Casta and Stephanie Seymour left (although Casta appeared in the 2002 What is Sexy commercial). Daniela Pestova left in early 2002. During that time, Gisele Bundchen and Adriana Lima were brought in as reinforcements. Alessandra Ambrosio was added in time for the Angels Across America tour in 2004 (and was the original "PINK girl") and Karolina, who had pretty much been doing Angel duties since 2002 anyways, was added in early 2005.
Because of Tyra's retirement in 2005 and Heidi's pregnancies, they added Selita and Izabel in late 2005, then Marisa in 2007, partly because they realized that they didn't have any American on the line-up anymore. Gisele left in 2007 and then PINK Girl Miranda Kerr was upgraded to Angel status. They also hired Doutzen Kroes in 2008 while Behati became the new PINK Girl. Kind of at the same time, Izabel left, supposedly for breach of contract. When Selita's and Karolina's contracts expired in 2008, they weren't renewed. In early 2010, Marisa disappeared from all VS-realted stuff leading people to believe she's no longer an Angel. Since then, she has been re-added as a Supermodel but only did the Swim catalog. Selita and Izabel are still walking at VSFS, as of the latest show.
And that's pretty much where we're at, with VS grooming Candice Swanepoel, Rosie Huntington, Lindsay Ellingson, Chanel Iman and Erin Heatherton to become Angels some day.
Chandra and Yasmeen probably never got "Angels contract" as it was just the beginning of the concept. Rebecca Romijn never did anything Angel-related but because some website (http://www.tvacres.com/admascots_angels.htm) said she did, people believed it and it even made it onto Wikipedia. Other models who were "featured" but not Angels: Eva Herzigova, Rhea Durham, Shakara Ledard, Daniela Urzi, Ana Hickman, Isabeli Fontana, Oluchi Onweagba, Ana Beatriz Barros, Deanna Miller, Susan Elridge, Jessica Van Der Steen, Linda Vojtova, This Girl, Angela Lindvall, Jessica Stam, Flavia de Oliveira, Emanuela De Paula, Kylie Bisutti, Jamie Lee Darley & other model search contestants, Brooklyn Decker, Jarah Mariano, Gracie Carvahlo, Aminata Niaria, Arlenis Sosa, Heloïse Guerin, Katsia Zingarevich...
The original Angels:
Yasmeen with the Angels: Laetitia as a Christmas Angel Elf:
Swim Angels: Angels 2000: Christmas Angels:
Angels in Cannes: Arena June 00 (no Gisele):
Angels across America: Late 2005: 2007 show:
2008 show: Now: