Several past women's champions of the Boston Marathon will return to race the course from Hopkinton to Copley Square on Monday for a chance to win another olive wreath crown. They'll face stiff competition in a historically fast women's field. Nineteen of the competitors have personal bests of under 2:23, including the three who have completed marathons in under 2:18."Boston is the oldest marathon. So even if I don't win, I will make my own story," said Hellen Obiri, last year's champion. She almost didn't enter the race last year, but now Obiri is hoping to defend her title. "You know that pressure you have among any champion – can I defend my title? So that thing is on my mind: How?" Obiri said.Edna Kiplagat, a two-time Boston winner, is an inspiration to runners everywhere at 44 years old, proving that age is just a number."I've run this course, and I know where the challenge is — the Heartbreak Hill," said Kiplagat."My challenge is, it's not about the course, it's about the field. Because every year, we have a very strong field. So you have to be mentally and physically prepared to face that challenge," Kiplagat added.Kiplagat moved to Colorado five years ago and recommended the training environment to fellow Kenyan Obiri. Obiri moved her family to Colorado last year, a decision that seems to have paid off as she went on to win Boston and then New York."You know that one gives you pressure when you win Boston and New York. So many people now will see how you will be doing your fourth marathon. So that one gives me a lot of motivation to work extra hard," said Obiri.Emma Bates, the top American finisher in last year's Boston Marathon, also trained in the steep elevations of Boulder, Colorado, with the singular goal of conquering the Boston Marathon."Just taking things day-by-day honestly is like the best way for me to get through anything, especially things that like mean a lot to me," said Bates.Bates was the top American finisher in last year's Boston Marathon. Her drive to make the US Olympic team was halted by a foot injury last fall. This unexpected turn of events changed her summer Paris Olympics plans but provided an opportunity to run Boston again."I feel like I'm coming at a great point going into the Boston Marathon because I feel like I have so much motivation and so much drive, more so even than last year. And that really fires me up because I think that I can really improve upon that fifth place," Bates added. Boston icon Des Linden, the 2018 champion, will be back on the field for her 11th Boston Marathon. She has finished the race in the top time five times. With the refined strategies of many experienced Boston Marathoners, this year's race promises to be another unpredictable and exciting women's race.