It's time to stop apologizing.
You shouldn't feel an obligation to convince anyone around you that your ideas and goals are valid. There comes a time that you will need to convince users, or customers, but at the start, when you just have an idea and you're excited about it, don't apologize for it.
It's fun to have others get excited, but what's even more fun is to be able to present an idea alongside work that supports the idea and brings it to fruition.
You don't need to apologize or defend your ideas at that first stage. Just let people know what you're going to be working on.