"We were absolutely stoked.
"I guess myself and mum and dad and the rest of the family were really excited," Sinclair said.
Her short-term goal with the Magic next year was to simply get on to the bench and take her chances if she got on to the court, she said.
Magic coach Julie Fitzgerald said the franchise was excited to be able to add such a promising young player to its roster.
"I first saw Sam on the court at the under-23 championships in Wellington recently and was impressed by her ability to read the play, feed the circle, and her work ethic. I think she has an exciting future and her game will flourish when given the opportunity to train and play with more experienced players.
"There is a maturity to Sam's game which defies her inexperience and she displays a real passion to learn and improve," Fitzgerald said.
Sinclair is looking forward to training alongside players she looked up to, although sadly fellow midcourter Laura Langman won't be among them. "Laura Langman has always been my sporting idol," she said. "I have had a few chances to train with her but now she has left [the Magic] she will be my competition."
Sinclair joins recent signings Jo Harten, Leana de Bruin and Brooke Leaver at the Magic, with further signings expected in the coming days. Magic had a squad of 14 players this year, and it is expected the squad will remain about that number.
Meanwhile, Sinclair's John Paul College senior A side are set to compete in the Upper North Island Secondary Schools A grade competition. She said if her school team could finish in the top six and qualify for the national championships it would be the perfect end to the year.