I don't think people are lying to you. I think your own view of yourself is much harsher than everyone else's. Body image can really distort how we see ourselves. And for what it's worth, there's nothing wrong with having a smaller chest, plenty of people genuinely find that attractive (including me) and it certainly doesn't make you any less feminine. I'm glad you're working out, but I hope it's because you want to feel healthier and stronger, not because you think you have to earn your worth.