“La Bamba” is a traditional son jarocho, the folk music of Veracruz on Mexico's Gulf coast, played at weddings with harps and small guitars. Its verses are playful boasts: to dance the bamba you need a little grace; I'm not a sailor, I'm a captain. Singers add and invent verses as they go.
In 1958 Ritchie Valens, a 17-year-old Mexican-American from Los Angeles, set it to a rock-and-roll beat. It became the first Spanish-language rock hit in the US. Valens died months later in the plane crash that also killed Buddy Holly; the 1987 film La Bamba, with Los Lobos' version, told his story.
The words are simple and old-fashioned, and the verses repeat, so it's a classic first song. Notice “una poca de gracia”: folk Spanish, not textbook — the standard would be “un poco de”.