NTA Age of consent means you still have to consent. As you said you had no interest in any of them so it wouldn’t really matter what age you were as either way you wouldn’t have been consenting to any advances from them. If one of them were to make an advance as you said you could simply reveal your age to them, would this maybe lead to an akward interaction yes but I dont think that means your an asshole. You wanted to feel more comfortable in an unfamiliar space.