Don't worry, it's totally normal to not have some crazy passion at your age, like most people are in the same boat. What works really well is choosing based on what you're good at rather than hunting for some mysterious passion - if math comes easy to you and you don't hate torturing yourself, that's already a good reason to stick with a science specialization. You can also tell yourself it's not set in stone, like, a lot of people completely change direction after high school, so don't stress your brain out about it now, just pick whatever seems the least annoying and that's it.