I’m a lesbian and although I have heard of Tegan & Sarah it’s probably been years since then! I don’t think it’s the most relevant association nowadays + Teagan is such a normal name anyway, I highly doubt anyone would think of it even if they were more familiar with them. Reading the title of your post, it didn’t come to mind at all! Worst case scenario you’ll get a light-hearted joke about it by other WLW around your age. Definitely not by your daughter’s peers!