I've been submissive my whole adult life but lately I've been having strong urges to top and dominate. Does this mean I'm not really a sub? I feel like I'm betraying who I am.
Impact PlayHaving dominant urges does not disqualify you as a submissive. Many people who identify primarily as one thing discover strong interest in the other side too. Switches are extremely common in BDSM, and your identity is yours to define regardless of what labels you use.
There is no rule that says a submissive must never want to top, just as there is no rule that a person who loves spicy food can never enjoy something mild. Erotic interests are not fixed categories that invalidate each other when they overlap.
The concept of a switch describes exactly this experience: someone who genuinely enjoys both the dominant and submissive roles, sometimes with different partners, sometimes at different times with the same person, sometimes depending entirely on mood. Switches are common enough to be considered a standard category in BDSM rather than an edge case.
What you might be experiencing is a perfectly natural expansion of your erotic imagination. Some people who have always submitted find that doing so for years gives them an unusually clear picture of what good domination looks like, and they become curious to practice it themselves. That insight can be a real asset.
You do not need to revise your whole identity over this. You can simply explore it, ideally with a willing partner in a negotiated context, and see whether it is a passing curiosity or something more substantial. Some people try topping and feel complete confirmation that they belong on the other side of the dynamic. Others find they love both and begin calling themselves switches. Both outcomes are valid, and neither one cancels out what you have been before.