Amajimbos secured their place in the global showpiece as a result of making it to the quarter-finals of the U17 Africa Cup of Nations.
Khumalo's side ended second in their qualifying group with four points from three games, five points behind Group B winners Burkina Faso.
Despite losing 2-0 to Burkina Faso in their last group game, the team progressed after Cameroon's 2-1 defeat to Egypt.
Khumalo revealed his happiness on SAFA's website, saying: "Let me take this opportunity to thank each and every South African who rallied behind us.
"And this is a great moment and a big achievement. I think initially, I made it clear that more than anything we want to qualify for the World Cup. So, it's mission accomplished. I'm very excited and delighted despite the last results which I think we still played well. We did not convert our chances, and we need to be a little bit more aggressive and direct.
“And I'm excited I'm happy, happy for the boys, happy for myself. A big challenge ahead of us playing at the world stage it means a lot and I'm looking forward and the boys and the technical team to the World Cup.”
Next up for Amajimbos is an AFCON quarter-final with Morocco on Thursday.
“With regards to the quarterfinals, we'll go back and strategize and plan thoroughly, but we will take this as part of practice, and we want to go through and through,” added Khumalo.
"Let's see how it goes. But I'm excited I'm happy. To all the South Africans I think we did not disappoint we qualified for the World Cup which was the main, main thing and the rest will just be the cherry on top. But I'm very, very happy and excited."
