Is it normal to have a bulge where I had inguinal hernia repair years ago?

May be recurrence. See your surgeon, may be repair broke down, and hernia recurred.
Possibly. The majority of bulges disappear after hernia surgery. Hematomas or aero as can present as bulges shortly after repair and typically resolve spontaneously. Very thin patients may notice a symmetrical bulge after surgery which could be the inferior aspect of the rictus muscle and normal. A bulge appearing late after surgery is likely to indicate a recurrence.
Can be. It can be normal, but make sure your doctor examines you to rule out possible recurrence.