Not quite, Mama Tiger. Properly speaking, one should never have to introduce oneself in a social setting; rather, the host or hostess should have introduced her to the gathering assembled. If you desire to know someone’s name and are unwilling to ask that person directly, one is obliged to ask a third party in the hopes that they might know.
I’m not in the habit of telling people I’ve changed my name. It’s not something they generally need to know. When she first entered the conversation, it would have been perfectly acceptable to say something like “I’m sorry, but I didn’t catch your name. Remind me again?” I have hundreds of acquaintances whose name I cannot recall, and there is no offense in forgetting the name of an infrequent companion, especially one who you have not seen for quite some time.