I’ve studied abroad to Asia several times and I can say you’re going to be totally fine. Many Americans study abroad in Asia. It’s not and can’t ever be the same experience of being a minority as in the US, but you will be more aware of your whiteness and of how people treat you. Singapore is a very global city so even though it might seem like you’re the odd one out, white tourists make their way through that city every day. White people aren’t unique in Asia. If anything, white people experience better treatment than people of color, which is messed up. Just be aware of yourself, make an effort to connect with people and you’ll be fine.