Diana Nyad is making another attempt to swim from Cuba to Florida after failing to reach her goal in August.
This time, the 62-year-old endurance swimmer from Los Angeles said she's ready for the planned 60-hour journey, which she began in Havana Friday night.
"I'm prepared and even saying that though, how many times do you get to do something of this big an adventure? You know, how many times do you get to feel this alive? This awake and alive?" Nyad said.
An asthma attack ended her attempt last month after 29 hours in the water. She was 15 miles off-course due to strong currents, according to Tweets on her page at the time.
Nyad is hoping to break her own world record for open-water swimming without a shark cage. A swimmer from Australia finished a swim from Cuba to the Florida Keys in 1997 but used a cage.
If she completes the swim, she would break her 1979 record, when she swam 102.5 miles from the Bahamas to Florida.
"I feel in better shape at 62 than I was at 28, which is the first time I tried this, 28 years old -- I'm not as fast as I was then and I'm a little fatter, uh, but that's OK," she said.
Well-wishers cheered Nyad on as she began her swim Friday.
"I know I'm going to be cold," Nyad told The Associated Press. "I know I'm going to run into all kinds of jellyfish and the nights are going to be long."
On Nyad's twitter account, her assistants have been updating the public of the swimmer's progress.
At one point, it appeared she was stung by a moon jelly.
"Diana was stung along both arms the side of her body and her face," chief handler Bonnie Stoll said in a message posted on her Twitter account.
After changing suits and rehydrating, Nyad continued her journey.
If all goes well, she predicts she will reach Florida early Monday morning, the AP reported.
ABC News' Enjoli Francis, Eric Noll, ABC News Radio and The Associated Press contributed to this story.