The track, which will serve as the follow-up to French Montana-assisted "I Luh Ya Papi", was produced by Max Martin and it is scheduled to be released next month, reported Ace Showbiz.
"First Love" was one of the songs that were played during an intimate brunch Lopez hosted in Malibu, California, on April 25.
"I wish you were my first love 'cause if you were first there wouldn't have been a second, third or fourth love," the track goes.
Lopez, 44, who is dating toyboy lover Casper Smart, said that love have been the recurring theme in most of his albums.
"After this experience, and these past couple of years, I realized love is completely different than I thought it was. I still believe in it more than ever. I'm still singing about it on every track, but I want it in the right way. I believe there's a certain way that it should be. The things I went through comes out here (on the album)," she said.