Sieglinde is first seen in chapter 17, jogging in training clothes with a hood covering her face. It is revealed in chapter 21 that in the previous year, she suddenly quit in the middle of the Inter-Middle although she won the championship couple of times before. She makes her unshadowed appearance in chapter 22, when the hood is pulled off by Victoria. She implies that she'll face off against Einhart Stratos in her fourth match.
(Source: Nanoha Wikia)
Sieglinde is the descendant of famous Jeremiah family. Her ancestor was the famous Belkan warlord and the one who gave to Olivia Sehbreht her magic arms and trained her in combat.
