A "nervous" Kai Trump shot a 13-over-par round on her LPGA debut as she ended the first day of the Annika tournament in last place.

The 18-year-old amateur, who is the granddaughter of US President Donald Trump, hit two double bogeys and nine bogeys in her opening round in Florida.

"I was definitely more nervous than I expected, but I thought I hit a lot of great shots out there. I hit a lot of good shots just to the wrong spots," said Trump.

"And obviously being my first LPGA event, now I kind of know how it goes. I felt like a little out of order in the beginning but I kind of got it going afterwards."

Trump has played only three events this year and is ranked number 461 in the American Junior Golf Association rankings.

She received a sponsor's exemption to play at the Annika but ended the first day four shots behind her closest competitor and 19 off the lead, held by South Korea's Haeran Ryu on six under.

"The whole time I was nervous without a doubt," said Trump. "I thought I did pretty good for just first time, being the youngest player in the field. I had a great time out there."

The LPGA said Trump's "broad following and reach are helping introduce golf to new audiences, especially among younger fans".

She has more than six million followers on social media and recently launched her own apparel and lifestyle brand.

England's Charley Hull and Ireland's Leona Maguire are three shots off the lead after shooting three-under-par 67s.