Talk to your manager about how much your pay is and ask if there was written documentation of how much your pay is.  They can tell you all you want that you get paid $x and get a raise after Y days, but you want to make sure that's all in writing and ask about what strings may be attached to getting that raise after 100 days.

Did you get a written agreement for what you would be paid?

Just got hired. But I looked at my check and im only making $12 how do i tactfully ask about this in text message format?

I was told id make $13 an hr and after a 100 days $14