I'm going to greet a good morning to all my colleagues today, it's extremely challenging for me

As I had been cold and stand offish the past couple weeks, as I'm new and I don't know what to do and mostly feel extra and annoying. My coldness discouraged some people from greeting me altogether.
Today I shall still feel like a wannabe trying to be cool and say "hi" to everyone, but I've gotta try. I should, right? As I'll be spending a significant amount of years here for my education.