Nah, some people might get offended right from the get go if you start talking about the basics with them, but it's only a problem if you continue to insist that you know better than them once it becomes clear they have an understanding of the topic. Like, if you're excited to talk about dinosaurs and the person you're talking to is a paleontologist, but you pivot to talking about deeper aspects of the topic once you realize, you're all good! Even better if you start asking them questions to learn from their expertise.

On the other hand, if you realize that they are a paleontologist and completely disregard that, insisting to them that you actually know more than them, or continue trying to explain base concepts, then yeah, you're a jerk.