Erectile dysfunction (ED) is characterized by issues with getting or maintaining an erection, while premature ejaculation is characterized by ejaculating too quickly during most or all sexual penetration. What's too quickly? It's often defined as less than a minute into a sexual experience, but it can be longer, depending on how much control you feel when you climax.
Premature ejaculation is also characterized by negative personal consequences. In some cultures, early ejaculation can be a sign of masculinity, so it's not considered a problem. But if you feel distressed, worried, or annoyed by the speed of your climax, or if your relationship is suffering because of it, a clinician might be able to help.