American Danielle Collins reached her first Grand Slam tennis final at age 28 on Thursday ― and played it cool.The 30th-ranked Collins’ 6-4, 6-1 demolition of No. 9 Iga Swiatek in the semifinals of the Australian Open may very well be the highlight of her previously unsung career. But she appeared nonchalant immediately afterward.In a press conference later, she said her favorite matches to watch as a youth involved Serena and Venus Williams. “To be playing on this stage where so many of my idols as a kid [were] playing, it’s almost surreal,” she said.Collins will face top-ranked home-country favorite Ash Barty in the championship.