I got waitlisted for into my program to come to Japan but I got in! Once I arrived, the fact that i was waitlisted instead of beign accepted from the beginning was irrelevant. I do my job just as well as the people who had been accepted.
I think having "imposter syndrome" is so common in this field. Even after finishing school, it seems like a lot of people struggle with accepting that they CAN do the job and do it well. Know you're not alone in your feeling but also know it's unwarranted and you'll do great <3 Your waitlist is irrelevant now that you're in. Make the best of it!