Calculating the next calendar birthday.

I have a form that is asking for the date of birth. Calculating the age is not a problem.

What I would like is a hidden field with the next birthday to use in the Calendar Report. I just can't come up with a working formula for updating that field value. Any ideas?

Took a bit more cogitation...
This has to be a Date field with an update field condition. Form Calculation will not work. I've noticed some dates are one day off, but this works well to populate the Calendar Report to show birthdays for upcoming year.

Thank you for the update. To my understanding, you want to pass the value of the "Next Birthday" date field to a hidden text field is that correct? I can see that you were able to create a formula that will calculate for the next birthday and it is working as I have tested it. I have cloned your form and created a Calendar report. Everything seems to be working fine. Is there anything else that you need to do that we can help you with? Please feel free to let us know should you have any other questions or concerns. Thank you.