Can I get a sixpack in 100days. I'm 180cm and I weight 78kgs. My bodyfat% is around 12-13?

If you are truly at a 12-13% body fat, with proper nutrition 100 days should be ample time to see abdominal definition. The biggest factor will be manipulation in your diet. When it comes to abs it's all about the diet. No matter how much an work you do. If your diet isn't dialed in properly you likely won't see the abs you're looking for.