Can we talk about CP time?  

It's a thing.  And if you come from a cultural or family background where starting times are more of a suggestion than a mandate, it can be a real challenge.  

Whether you believe this to be rooted in our cultural differences or a pernicious and offensive stereotype, the truth is many of your new coworkers may be primed to expect you to be late to work just because of your skin tone.  When you are, they will be quick to be resentful, assuming you think you can flout the rules everyone else must follow.  

If you're Punctual Pam and believe "to be early is to be on time and to be on time is to be late," this may not be a problem for you.  But, if you're like me, where being within 15-30 minutes of the discussed start time is considered on time, if not early, this may be something you have to adjust for in your career.