I'm a teen. my eyes are healthy but my vision keeps getting worse every year? (nearsighted) - can i go blind if my vision keeps getting worse?

Unlikely: It is not unusual for some gradual changes in vision from early childhood through the teen years due to growth changes. Once you are past adolescence, things tend to stabilize. People still need to have their eyes checked on a regular basis through life, but this includes the value these checks have in monitoring the rest of your internal health.